ATOMIC STRUCTURE IIT I IT QUESTIONS Single answer type questions :
1.
Sele Selecct th the corre rrect sta state teme ment nt : 1) Orbital angular momentum is
2.
3.
4.
é
h ( ll 0 )
1 ù2
7.
for the electron having n = 5 and lower value of the
1 é h ( l0 - l ) ù 2
2) ê
1 é h ( l - l 0 ) ù 2
1 é hll 0 ù 2
3) ê 4) ê ú ú mc mc 2 ll 2 ll ë 2mc úû 0 û 0 û ë ë From the followi following ng observ observation ation of Mr. Mr. Gupta, Gupta, Mr. Mr. Agarwal Agarwal and Mr. Mr. Maheshw Maheshwari ari predic predictt the type type of orbital Mr. Gupta : The angular function of the orbital intersect the three axes to origin only Mr. Agarwal : XY plane acts as a nodal plane Mr. Maheswari : The graph of radial probability probabilit y v/s ‘r’ intersects the radial axis at three separate separate regions points including origin 1) 5dyz 2) 4pz 3) 6dyz 4) 6dxy The The pro probbabil abilit ityy of of fin findi dinng the the elec electr tron on is maxi maximu mum m for for dx2- y2 orbital in 1) along x-axis only 2) along y-axis only 3) along x, y axes 4) be betwe tween x, y axes Whic Whichh one one of the the fo follo llowin wing sta state teme ment nt is not corre orrecct 1) Rydber Rydberg’ g’ss constant constant and and wave number number have have same same units 2) Lymon ymon series of hydroge hydrogenn spectrum spectrum occurs occurs in UV region
ú
ë 2mc ( l0 - l ) û
6.
p
azimuthal quantum number 2) If n = 3, L = 0, m = 0 for the last valence shell electron, then t hen the possible atomic number numb er may be 12 or 13 7 3) Total spin of electrons for the atom (Z = 25) 25) Mn is + 5 4) Magnetic moment due to spin for nobel gas is zero Ident dentif ifyy the the corr correect sta state teme ment nt(s (s)) I) The radial probability distribution distributi on curves for 1s, 2s, 2p and 3d are identical II) The number of nodal planes for 2p, 3p and 4p orbitals is same III) Theoretically Theoretically calculated spin only magnetic moment is same for Ti+2 and Ni+2 IV) A ‘P’ orbital can accomodate a maximum max imum of six si x electrons 1) I and and II II are are correc correctt 2) II and and III III are corr correc ectt 3) III III and IV are are corr correc ectt 4) Only Only IV is corr correc ectt x+ y+ The mag magnetic etic mome oment of of two two ion ions M and M of the element M(z = 26) is found to be 5.916 BM. If x > y, y, then which of the following fol lowing statement is correct 1) My+ is more stable than Mx+ 2) My+ is less stable than M x+ 3) Both Both are equal equal stable stable 4) Cannot Cannot be predicted predicted If l0 is threshold wavelength wavelength for photoelectric photoelectric emission, l wavelength of light falling on the surface of metal, and m, mass of electron, then de Broglie wavelength of emitted electron is 1) ê
5.
h
3) The angular angular momentum momentum of the electron electron into the the ground ground state hydroge hydrogenn atom is equal equal to
h 2π
8.
4) The radius radius of first first Bohr Bohr orbit orbit of hydrog hydrogen en atom atom is 2.116 2.116´10-8 cm Whic Whichh one one of the the fol follo low wing ing sta state teme mennt is is cor corre recct 1) 2S orbital orbital is is spheric spherical al with with two nodal nodal plane planess 2) The debro debrogo golic lic wav wavel elen engt gthh (l) of a particle of mass m and velocity vel ocity v is equal to
mv h
3) The princip principal al quantum quantum number number n indicat indicates es the shape shape of orbital orbital 9.
10.
4) The electronic electronic configu configuration ration of phosphorous phosphorous is given by Ne 3S2 3p1x p1y p1z What What is true true regardi regarding ng the the length length of of photogr photographi aphicc film occup occupied ied by by vario various us series series in hydrog hydrogen en emissio emissionn spectrum? (L1 : Length of Lyman series; L2 : Length of Balmer series; L3 : Length of Paschen series) 1) L1 = L2 = L3 2) L1 < L2 < L3 3) L1 < L2 > L3 4) L1 > L2 > L3 th + Photons Photons having having energy energy equival equivalent ent to bindin bindingg ener energy gy of 4 state of He ion is used the metal surface of work function 1.4 eV. eV. If electrons are further accelerated accelerat ed through the potential difference of 4 V then the minimum value of de-Broglies wavelength associated with the electron is o
1) 1.1. A
11. 11.
12. 13.
14. 15. 16.
o
o
2) 9.15 A
o
3) 5 A 4) 11 A 2h h to during a transition in a hydrogen atom, If the the angu angula larr moment momentum um of an an electr electron on cha chang nges es from from p
p
it results in the formation of spectral line is 1) mv region 2) visible region 3) IR region 4) Far IR region Proton, Proton, Alpha Alpha parti particle cless are are acc acceler elerate atedd with with same same poten potential. tial. The de Brog Broglie lie wavelen wavelength gth ratio ratio is 1) 2 2 : 1 2) 1 : 2 2 3) 4 : 1 4) 1 : 4 A stationary He+ ion emitted a photon corresponding to the first line of the Lymen Lymen series. The photon liberates a photo electron from a stationary hydrogen hydrogen atom in ground state. The kinetic energy of electron is 1) 10.2 eV 2) 13.6 eV 3) 20.4 eV 4) 27.2 eV The The unc uncer erta tain inty ty in posi positio tionn is is of of the the orde orderr of of 1A0. The uncertainty in velocity of a cricket ball (0.1505 kg) is 1) 1.7´10-23 m/ m/sec 2) 1.7´10-24 m/ m/sec 3) 3.4´10-23 m/ m/sec 4) 3.4´10-24 m/sec A standi standing ng wave wave in a string string 35cm 35cm long long has has a total total of of six node nodess includ including ing ends ends.. Hence Hence wav wavee length length is 1) 14 cm 2) 5.82 cm 3) 7 cm 4) 17.5 cm The m valu valuee for for an an elec electro tronn in an atom atom is equal equal to the the numb number er of of m valu values es for l = 1. The electron may be presen presentt in 1) 3d x 2 - y2 2) 5f xyz 3) 2Px 4) 3 S
17.
An elec electro tronn tra trave vels ls with with vel veloc ocity ity of v ms –1. For a proton to have the same de-Broglie wavelength, the velocity will be approximately 1) v ms –1 2) 1840 v ms –1 3) v/1840 ms –1 4) 1840/v ms –1
18.
The dye dye Acriflavin Acriflavine, e, when when dissolved dissolved in water water,, has its maximum maximum light light absorp absorption tion at 4530 4530 A and the
0
0
maximum fluorescence emission at 5080 A . The number of fluorescence quanta is, on the average 53% of the number of quanta absorbed. Using the wavelengths of maximum absorption and emission, what percentage of absorbed energy is emitted as fluorescence?
1) 100% 2) 47% 3) 36% 4) 12% 19. A gaseo gaseous us particle particle ‘X’ has a proton proton (atomic) (atomic) number number ‘n’ and a charge charge of of +1. An An another another gaseous gaseous particle particle ‘Y’ has a proton proton (atomic) (atomic) number number of (n + 1) and is isoelect isoelectroni ronicc with X. Which of the following statements correctly describe X and Y? 1) X has larger radius than Y 2) X requires more energy than Y when a further electron is removed from each particle parti cle 3) X releases more energy than Y when an electron is i s added to each particle 4) X and Y both has same electronegativity 20. When When an electron electron is transite transitedd from 2E to E energ energyy level, level, the wavele wavelength ngth of of photon produce producedd is l1. If electronic transition transi tion involves 4/3 E to E level, the wavelength wavelength of resultant photon is l2. Which of the following is a correct relation? 3 4 = 4) 1 2 1 4 2 If a certain certain metal metal was irradia irradiated ted by using two two different different light light radiation radiationss of frequenc frequencyy ‘x’ and and ‘2x’, the kinetic energies of the t he ejected electrons electr ons are ‘y’ and ‘3y’, respectively respectivel y. The threshold frequency f requency of the metal will be :
1) l2 = l1
21.
23. 24.
25.
x
2)
1) 6.55 ´ 1015 26.
3)
2 =
3 x 2 x 4) 3 2 2 3 During During the excitatio excitationn of an electro electron, n, it travels travels at a distan distance ce of nearly nearly 0.795 0.795 nm in the hydrog hydrogen en atom. atom. The maximum no. of spectral lines formed during duri ng the de-excitation is 1) 1 2) 3 3) 6 4) 10 The ratio ratio between between the the wave number numberss of spectra spectrall lines of Balmer Balmer series series of hydrog hydrogen en having having the the least least and the highest wavelength values is 1) 5 : 27 2) 27 : 5 3) 5 : 9 4) 9 : 5 The number number of nodal planes, planes, radial nodes and peaks peaks in the radial radial probability probability curve of 5d orbital orbital are are respectively 1) 5, 2, 3 2) 4, 3, 2 3) 2, 3, 2 4) 2, 2, 3 The number number of revo revolutio lutions ns made made by electron electron in Bohr’ Bohr’ss 2nd orbit of hydrogen atom in one second is
1)
22.
2) l2 = 3l1
x
3)
2) 8.2 ´ 1014
3) 1.64 ´ 1015
4) 2.62 ´ 1016
When When an excited excited state state of H-atom H-atom emits a photon photon of waveleng wavelength th l and returns to the ground state, the princi principal pal quantu quantum m numbe numberr of excite excitedd state state is given given by 1)
(
R -1) R
2)
R ( R -1)
R
3) ( R -1)
4)
R ( R
1)
27.
What What is the maximum maximum number number of electr electrons ons in an atom atom that that can have have the followi following ng quantum quantum numbe numbers rs n = 4, m1 = +1? 1) 4 2) 15 3) 3 4) 6
28. 28.
The wave func unctio tion (Y) of 2s is given by ( Y ) = 1 2s 2 2
1/ 2
æ 1 ÷ö çç ÷ ÷ èç a ÷ø 0
æ ö çç2 - r ÷÷ e-r / 2 a 0 at r = r , radial node 0 ÷ çè a0 ÷ø
is formed. Thus for 2s, r 0 in terms of a0 is 1) r 0 = a0 29.
2) r 0 = 2a 2a0
3) r 0 = a0/2
4) r0 = 4a 4a0
Which of the the following following statements statements in relatio relationn of the hydroge hydrogenn atom atom is correct? correct? 1) 3s, 3p and 3d orbitals all have the same energy 2) 3s and 3p orbitals are of lower energy than 3d orbital
30. 30.
31.
3) 3p 3p orbita orbitall is lower lower in energy energy than than 3d orbital orbital 4) 3s 3s orbital orbital is lower lower in ener energy gy than 3p orbita orbitall Choo Choose se wron wrongg sta state teme mennt 1) The shape of an atomic orbital depends upon azimuthal quantum number 2) The orientation of an atomic orbital depends upon the magnetic quantum number 3) The energyof an electron in an atomic orbital of multi-electron multi-electron atom depends upon principal quantum number only 4) The number of degenerate atomic orbitals orbi tals of one type depends upon the value of azimuthal azimut hal and magnetic quantum number only The ground ground state electro electronic nic configur configurations ations of the elements, elements, U, V, V, W, W, X and Y (the symbols symbols do not not have any chemical significance) are as follows U 1s22s22p3 V
1s22s22p63s1
W
1s22s22p63s23p2
X
1s22s22p63s23p63d54s2
Y 1s22s22p63s23p63d104s24p6 Determine which sequence of elements satisfy the following statements I) Element-forms a carbonate which is not decomposed by heating II) Element-is most likely to form coloured ionic compounds III) Element-has largest atomic radius IV) Element-forms only acidic oxide 1) V W Y U 2) V X Y W 3) V W Y X
4) V X W U
32.
If the quantu quantum m numbe numberr are are define definedd as as follo follows ws : n = 1, 2, 2, 3 ...... .......... , l = 0, 1, 2, ...... (n + 1), m = – l in integral steps to +l. How many electrons could be fitted fitt ed in Ist shell 1) 2 2) 8 3) 10 4) 18
33.
If electron electronss were to fill up progres progressive sively ly with orbit orbit saturation saturation (neglec (neglecting tingAuf Bau rule) rule) and each each orbital orbital were to accommodate the three electrons, instead of two; which of the following fol lowing would NOT hold correct for the new electronic arrangement in Zirconium atom (Z = 40)? 1) The number of p-electrons would be double the number of s-electrons 2) Spin quantum number would become super flows 3) Zirconium would conti continue nue to belong to the 4th period (in new periodic table) 4) Zirconium would show retention of block If the above radial probability probability curve indicates 2s orbital, orbital, the distance distance between the peak peak points points x, y is
34.
0
0
0
0
35.
1) 2.07 A 2) 1.59 A 3) 0.53 A 4) 2.12 A An electron electron is contin continuous uously ly acce accelerat lerated ed in a vacuum vacuum tube tube by apply applying ing potentia potentiall difference difference.. If the de-Broglie’s wavelength is decreased by 10%, the change in the kinetic energy of electron is nearly nearl y 1) decr decrea ease sedd by by 11% 11% 2) incr increeased ased by 23.4 23.4% % 3) incr increa ease sedd by by 10% 10% 4) incr increa ease sedd by by 11.1% 1.1%
36.
The The angul ngular armome moment ntum umofele electro ctronn inLi2+ was found to be (7h/11). (7h/11). The distance of the electron from nucleus is is
0
37.
38.
0
0
0
1) 1.69 A 2) 0.68 A 3) 2.82 A 4) 8.19 A The frequency ‘n’ of certain line of the Lyman Lyman series of the atomic spectrum of hydrogen satisfies the following conditions I) It is the sum of the frequencies of another Lyman Lyman line and a Balmer li line ne II) It is the sum of the frequencies of a certain line, li ne, a Balmer line and a Paschen line III) It is the sum of the th e frequencies of a Lyman and a Paschen line but no Brackett line To what transition transit ion does n correspond? 1) n2 = 3 to n 1 = 1 2) n2 = 3 to n 1 = 2 3) n2 = 2 to n1 = 1 4) n2 = 4 to n1 = 1 A hydrog hydrogen en atom atom sampl samplee in the ground ground state state is excite excitedd by monochro monochromati maticc light light radia radiation tion of wavewave0
length l A . The resulting spectrum consists of maximum 15 different different lines. What is l? (R H = 109677 cm –1) 0
0
0
1) 937.3 A 2) 1025 A 3) 1236 A 4) None of these 39. The ratio ratio between between time perio periods ds taken taken by electro electronn in Bohr’ Bohr’ss 2nd 2nd and and 3rd orbits orbits for for each each revol revolution ution is 1) 9 : 4 2) 4 : 9 3) 8 : 27 4) 27 : 8 th 40. 40. The ve veloc locity ity of an ele elecctro tron in n orbit of hydrogen atom bears the ratio 1 : 411 to the velocity velocity of light. The number of coloured lines formed when electron jumps from (n+3) state stat e to ground state. 1) 4 2) 3 3) 5 4) 6 41. The The dede-Br Brog ogli liee wav wavee len lengt gthh (l) of electron is related relat ed to its accelerating potential (V) by the equation : 1) 42.
43. 43.
44.
45. 46. 46.
47. 48.
( A0)
=
12.27 V
2)
(nm)
=
12.27 V
3)
( A0)
=
150 V
4)
(nm)
=
150 V
Hydro Hydrogen gen-lik -likee ion has has the the wavele waveleng ngth th differ differenc encee betwee betweenn the first first lines lines of of Balmer Balmer and and lymen lymen serie seriess equal to 33.4 nm. The atomic number number of that ion equal to 1) 4 2) 3 3) 2 4) 5 When When a cert certai ainn meta metall was was irra irradi diat ated ed with with ligh lightt of fre frequ quen ency cy 3.2 ´ 1016 Hz. The photo photo clectrons clectrons emitted has twice the kinetic kineti c energy as as did photoelectrons emit emitted ted when the same metal was irradiated with light li ght of frequency 2.5 ´ 1016 Hz. . The threshold frequency frequency of the metal is ______ 1015 Hz. 1) 18 2) 20 3) 22 4) 16 What What is the wav wavele eleng ngth th of the the photo photonn emitted emitted by by a hyd hydrog rogen en atom atom when when an electr electron on make makess transit transition ion from n = 2 to n = 1. Given that ionization potential is i s 13.786 eV. eV. Answer expressed in Angstrom units 1) 1200 2) 900 3) 800 4) 1000 The ratio ratio of the the energy energy of the the electr electron on in grou ground nd state state of of hydro hydroge genn to the the electr electron on in first first exci excited ted stat statee 3+ of Be is 1) 1 : 4 2) 1 : 8 3) 1 : 16 4) 16 : 1 5 1 4 2 The The con conffigu igurati ratioon of of Cr Cr ato atom m is is 3d 3d 4s but not 3d 4s due to reason R 1 and the configuration of Cu 10 1 9 2 atom is 3d 4s but not 3d 4s due to reason R 2. R 1 and R 2 are are 5 1 1) R 1 : The exchange energy of 3d 4s is greater than that of 3d4 4s2. R 2 : The exchange energy of 3d10 4s1 is greater than that of 3d9 4s2. 2) R 1 : 3d5 4s1 and 3d4 4s2 have same exchange energy but 3d 5 4s1 is spherically symmetrical. R 2 : 3d10 4s1 is also spherically symmetrical 3) R 1 : 3d5 4s1 has greater exchange energy than 3d 4 4s2. R 2 : 3d10 4s1 has spherical symmetry. symmetry. 5 1 4) R 1 : 3d 4s 4s has greater energy than 3d 4 4s2. R 2 : 3d10 4s1 has greater energy than 3d 9 4s2. M axi mum value value (n+l+m) for unpaired electrons in second excited state of chlorine 17Cl is 1) 28 2) 25 3) 20 4) none of these If r is the radius radius of of first first Bohr’ Bohr’ss orbit orbit for hydro hydrogen gen atom. atom. The de Broglie Broglie wavele waveleng ngth th in the nth orbit of hydrogen atom is given by
49.
50. 50.
51.
1) 2πr n 2) 2πr.n 3) 2πr n 2 4) 2πrn 2 When When two elec electron tronss are prese present nt in two two dege degener nerate ate,, orbita orbitals ls of an an atom, atom, the energy energy is lower lower if if their their spin is parallel. The statement is based upon 1) Pauli’s exclusion principle 2) Aufbau principle 3) Hund’s rule 4) Bohr’s rule If the the nit nitro roge genn ato atom m had had elec electr tron onic ic con config figur urat atio ionn 1s7, it would have energy lower than that of the normal ground state configuration 1s2 2s2 2p3, because the electrons would be closer to t o the nucleus. et 1s7 is not observed because it violates. 1) Heisenberg uncertainly principle 2) Hund’s rule 3) Pauli exclusion principle 4) Bohr postulate of stationary orbits If RH is the Rydberg constant, then the energy of an electron in the ground state of hydrogen atom is hC 1 R HC 2) R 3) R Ch 4) - R H hC h H H When electronic electronic transition transition occurs occurs from from highe higherr energ energyy state state to a lower lower energy energy state with energy energy differdifference equal to DE eV. The wavelength of line emitted is approximately equal equal to
1)
52.
53. 54. 55.
56. 57.
12400 ´10 -10 13397 ´1010 14322 ´10 -10 12387 ´1010 m m m cm 1) 2) 3) 4) DE DE DE DE In Mos Mosde dey’ y’ss equa equatio tionn give givenn cons constan tants ts a = b = 1 the thenn the the freq freque uenc ncyy is is 100 100 sec sec -1. The element will be 1) K 2) Na 3) Rb 4) Cs Whic Whichh of the the pai pairr of orb orbita itals ls hav havee elec electro tronic nic dens density ity alon alongg the the axis axis 1) dxy dyz 2) d x 2 - y2 d z2 3) dx y dx z 4) d xy d z2 If azimuthal azimuthal quantum quantum number number could could have value value of of n also also in additi addition on to to normal normal value, value, then then E.C E.C of Cr(z = 24) would have been 1) 1s2 2s2 2p6 3s2 3p6 4s2 3d4 2) 1s2 2s2 2p6 3s2 3p6 4s1 3d5 3) 1s2 1p6 2s2 2p6 3s2 2d6 4) 1s2 1p6 2s2 2p6 2d6 In radial radial prob probabil ability ity distribu distribution tion curve curve of of 2s orbital orbital the distanc distancee betwe between en two peaks peaks is is 1) 0.53 2) 2.1 3) 1.1 4) 1.57 If n and l are respectively respectively principal, Azimuthal quantum numbers, then the expression for calculating the total number of electrons in any energy energy level is l =n-1
1) 58.
å
l = 0
l =n
2 (2 (2 l + 1 )
2)
2(2l +1) å 2(
l = 1
l =n
l =n-1
3)
å
l = 1
2( 2(2l + 1 )
4)
2( 2(2l +1) å = 0 l
Consid Consider er follow following ing statem statemen ents ts conc concern erning ing the sub shell shell’’s of of (I) (I) The The ma maximu ximum m va value lue of of m for g su sub sh shell is 4 (II) (II) The The max maxim imum um no. no. of of unp unpai aire redd ele elect ctro rons ns in g sub sub she shell ll is 9 (III) (III) The lowest lowest value value for the shell shell havi having ng of g sub shell shell is is 5 Select correct statements 1) II, I only 2) II, III only 3) I, III only 4) I, II, III -1 59. If a 1 gm body body is tra trave velli lling ng alon alongg the the X-ax X-axis is at at 100 100 cm sec sec within 1cm sec-1 then uncertainty in its posi positio tionn is 1) 2.64 ´ 10-30 m 2) 5.28 ´ 10-30 m 3) 1.32 ´ 10-30 m 4) 0.66 ´ 10-30 m 60. The photoelec photoelectric tric emission emission requires requires a thresh threshold old frequency frequency V0 for a certain metal l1=2000Å and l2=1660Å produce electrons electrons with kinetic energy energy KE KE1 and KE2 of KE2 = 2KE1. The threshould requency V0 is 1) 1.15 ×1015 sec –1 2) 1.15 ×1014 sec –1 3) 1.19 ×1015 sec –1 4) 1.19 ×1014 sec –1 61. Calculate Calculate the waveleng wavelength th emitted emitted during during the the trastition trastition of electr electrons ons in betwe between en two levels of Li+2 ion whose sum is 4 and differ difference ence is 2 –6 1) 1.14×10 cm cm 2) 1.14×10 –5 cm cm 3) 2.12×10 –6 cm cm 4) 2.14×10 –5 cm
A cert certai ainn dye dye abs absor orbs bs lig light ht of of l =4700Å and then fluorencene light of XÅ. Assuming that 47 % of absorbed light is reemitted as fluorescence. The ratio of quanta emitted out to the number of quanta absorbed is 0.5. The value of X is 1) 4000Å 2) 5000Å 3) 5500Å 4) 6000Å 63. The bond bond dissoci dissociation ation of of H-H bond bond is 400 KJ/mole. KJ/mole. The energ energyy require requiredd to excile excile 0.04 mole mole of Hydrogen gas to the first excisel state of hydrogen atom is 1) 94.6 KJ 2) 47.3 KJ 3) 70.9 KJ 4) 80.4 KJ 64. The angular angular momentum momentum of an electron electron in a Bohr’s Bohr’s orbit of hydroge hydrogenn atom atom is 4.217 ×10 –34 kg - m2/sec. The no. of specifed lines formed is visible region when electron fallls from this level is 1) 4 2) 3 3) 2 4) 6 65. What What transition transition in the the hydroge hydrogenn spectrum spectrum would would have have the same same wavele wavelength ngth as as the transitio transitionn n = 4, n =2 + in He ion 1) 4 ® 2 2) 3 ® 1 3) 3 ® 2 4) 2 ® 1 66. If the radiu radiuss of of firs firstt Boh Bohrr orbi orbitt is is X1 then deBroglie wavelength of electron is 3rd orbit is nearly : 1) 2 p x 2) 6 p x 3) 9x 4) x/3 th 67. The The ang angul ular ar spee speedd of of the the elec electro tronn in in n orbit of Bohr hydrogen atoms is 62. 62.
68.
1) Directly propertional to n 2) Inversly propertional of n 2 3) Inversly propertional to n 4) Inversly propertional to n3 In hydro hydroge genn atom atom,, the the elec electro tronic nic motion motion is repr represe esente ntedd as as follo follow w. The The numbe number r of revolutions revolution s made by that electron in one second is equal to 1) 6.5 ´ 1015 2) 2 ´ 1014 3) 2 ´1013
69.
4) 1.01´1014
70. 70.
The length length of of the minor minor axis axis corre correspon sponding ding to the the ellipt elliptical ical path for which which n = 4 and k = 2. 0 0 0 1) 8.464 A 2) 16.92 A 3) 2.116 A 4) 4.23 A0 In whic whichh qua quant ntum um leve levell does does the the ele elect ctro ronn jump jumpss in He+ ion to ground state if it is given an energy corresponding to 99% of the ionisation potential of He+ ion. 1) 4 2) 6 3) 8 4) 10
71.
Whic Whichh amon amongg the the foll follow owin ingg is corr correc ectt of 5B in normal state
72. 73. 74.
1)
: Against Hund’s Hund’s rule
2)
: Against Aufbau principle as well as Hund’s Hund’s rule
3)
: Violation of Pauli’s exclusion exclusio n principle principl e and not Hund’s rule
4) : Against Aufbau principle How many many times times does does light light travel travel faste fasterr in vaccu vaccum m than than an elec electron tron in in Bohr’ Bohr’ss first first orbit orbit of hydrog hydrogen en atom? 1) 13.7 times 2) 67 times 3) 137 times 4) 97 times When a hyd hydroge rogenn atom atom emitts emitts a photon photon of energ energyy 12.1 eV. eV. The orbit angular angular momentum momentum changes changes by 1) 1.05 ´ 10-34 J.sec 2) 2.11´ 10 -34 J.sec 3) 3.16 ´ 10 -34 J.sec 4) 4.22 ´ 10 -34 J.sec If kinetic kinetic energy energy of a part particle icle is doubled doubled;; de Brogli Brogliee wavele wavelengt ngthh beco becomes mes 1) 2 times
2) 4 times
3) 2 times
4) 1
2 ti times
75.
Imagin Imaginee an atom made up of of a proton proton and and a hypothe hypothetica ticall particle particle of double double the mass of the the electr electron on but having the same charge charge as the electron. Apply the bohr atomic model and consider possible transitions of this hypothetical particle to the first excited level. The largest wavelength of photon that will be emitted has wavelength λ equal to (R is Rydberg Rydberg constant) 9 36 18 27 2) 3) 4) 5R 5R 5R 5R When When a certa certain in meta metall was was irra irradia diated ted with with light light havi having ng a freq freque uenc ncyy of of 3.0 ´ 1016 sec-1. The photo electrons emitted had twice the kinetic energy as did photoelectrons emitted when the same metal was irradiated with light light having a frequency of 2.0 ´ 1016 sec-1 . The threshold frequency of metal (in 1016 sec-1) is 1) 1 2) 2 3) 3 4) 4 Give Givenn ioni ionisa sati tion on pot poten enti tial al of of hydr hydrog ogen en atom atom is is 2.0 ´ 10- 18 J Plank’s constant is 6.0 ´ 10- 34 J.sec.
1)
76.
77. 77.
78. 79. 79. 80. 81. 82. 83.
The frequency H β line in Balmer series is in the values of (1012 Hz) is 1) 625 2) 840 3) 925 4) 520 The radius radius of of the orbit orbit in hydro hydroge genn atom atom is 0.84 0.8464n 64nm. m. The veloci velocity ty of elec electron tron in this this orbit orbit (in (in the the 3 order of 10 m/sec) is 1) 547 2) 637 3) 342 4) 832 2+ The The cal calccula ulated ted ma magneti neticc mom momeent of of Cr Cr is 1) 1.73 BM 2) 2.8 BM 3) 4.8 BM 4) 5.9 BM 2+ The no no. of of d electrons in in Fe Fe is not equal to that of 1) p-e p-elec lectron tronss in in Ne Ne 2) s-e s-elec lectro trons in Mg 3) p-e p-ele lecctro trons in Cl - 4) p-electrons in Mg De Brog Brogli liee wav wavel elen engt gthh of of the the Bohr Bohr firs firstt orb orbit it is is λ . The circumference of the Bohr fourth orbit is 1) 4 λ 2) 8 λ 3) 16 λ 4) 2 λ What hydroge hydrogenn like like ion ion has has the the waveleng wavelength th differe difference nce between between the first line of Balme Balmerr and and Lym Lymen en series equal to 133 nm 1) He+ 2) Li+2 3) Be+3 4) 13+4 The shor shortes testt wavel waveleng ength th of hyd hydrog rogen en atom atom in in Ly Lyman seri series es is X. The longes longestt wavele waveleng ngth th in Balme Balmer r series of He+ is 9x 36x x 5x 2) 3) 4) 5 5 4 9 Pick Pick out out the corre correct ct optio option. n. Wher Wheree T stand standss for for true. true. F sta stand ndss for for false false.. (a) The energy of the 3d orbital is high hi gh when compared to 4s orbital in i n hydrogen atom
1)
84.
85.
86. 87.
(b) The electron density in xy plane in d x 2 - y2 orbital is zero (c) 24th electron in Cr goes to 3d orbital (d) The three quantum numbers were clearly explained in terms of schrodinger wave equation 1) TTFF 2) TFTT 3) TFTF 4) FFTT 0 The The unc uncer erta tain inty ty in posi positio tionn is is of of the the orde orderr fo fo 1A . The uncertainty in velocity of a cricket ball (0.1505 kg) is 1) 1.7 ´ 10- 23 m/sec 2) 1.7 ´ 10- 24 m/sec 3) 3.4 ´10- 23 m/sec 4) 3.4 ´ 10- 24 m/sec The velocity velocity of electron electron in a certain certain Bohr Bohr orbit orbit of of hydrog hydrogen en atom atom bears bears the the ratio ratio 1 : 275 to the the velocity velocity of light. So the no. of orbit is 1) 1 2) 2 3) 3 4) 4 If the there re were were three three poss possibi ibilit litie iess of ele electr ctron on spin spin,, k(19) k(19) wou would ld be be plac placed ed in in 1) s block 2) p block 3) d block 4) f block
88. Consider Consider the followin following g plots plots for 2s–orb 2s–orbital itals s y
x
z
r
r (I)
(II)
r (III)
x,y and z are respectively,
89.
90.
1) Y, Y2 and 4pr 2 dr Y2 2) Y2, Y and 4pr 2 dr Y2 3) 4pr 2 dr Y2 and Y2 and Y 4) Y2, 4pr 2 dr Y2 and Y For a hypot hypothe hetic tical al H like like atom atom which which follo follows ws Bohr’ Bohr’ss model, some spectral lines were observed as shown. If it is known that line ‘E’ belongs to the visible region, then the lines possibly belonging to ultra violet region will be (n1 is not necessarily ground state) [Assume for this atom, no spectral spectr al series shows overlaps with other series in the emission spectrum] 1) B and D 2) D only 3) C only 4) A only If any any subshe subshell, ll, the maximum maximum number number of of electrons electrons having having same same value value of spin spin quantum quantum number number is : 1) l (l 1)
91.
2) l + 2
3) 2l + 1
Given the wave function of an orbital of hydrogen atom;
4) 4l + 2
æ 1 ö -r /a y1,0 ÷e 1,0 = ç 3/2 è pa 0 ø
0
, the
most probable distance of the electron present in the given orbital from the nucleus is A) a 0 .e -2r
B) a 0
C) (3/2) a 0
D) 2a0
92. Given the correct correct order order of initials T(true) T(true) or F(false) F(false) for following following statements. statements. i) Maximum kinetic energy a photoelectron emitted from a metal [work function = 2eV] by a photon of wavelength 310 nm is 3.2 × 10 -19 J. ii) The ratio of magnitude of Total Energy: Kinetic energy: Potential Energy for any orbitis 1 : 1 : 2 iii) Number of maximum for the curve 4 pr 2R 2 (r ) v/s r are three for the 5p x orbital. iv) The ratio of de-broglie wavelength of a ‘H’ atom, ‘He’ atom and CH 4 molecule moving with equal kinetic energy is 4 : 2 : 1 A ) F FTT
93. 93.
B ) TTFT
C ) TF TF
D) FTTT
The diffe ifferrence nth and (n + 1)th Bohr’s radius of H-atoms is equal to (n – 1)th Bohr’s radius. Hence the value of ‘n’ is 1) 1 2) 2 3) 3 4) 4
Assertion (A) & Reason (R) type questions : 1) Both A and R are true and R is i s correct explanation of A 2) Both A and R are true and R is not correct explanation explana tion of A
3) A is true, R is false
4) A is false, R is true
101. Asserti Assertion on (A) : The The wave wave functio functions ns of p-ty p-type pe (l = 1) with the same value of ‘n’ but with different values of ‘m’ will have the same radial distribution function Reason (R) : Radial distribution function depends only on the values of ‘n’ and ‘l’ and not on the value of ‘m’ 102. Assertion Assertion(A) (A) : Accordin Accordingg to Bohr IE2 of He is 54.4 ev/atom 2 Z eff
Reason (R) : IE of atom is given by 13.6
n2
ev/atom
103. Assertion (A) : An electron electron can never be found in the nucleus Reason (R) : Velocity of the electron wave is less than the velocity of ligtht 104. Assert Assertion ion (A) (A) : No two electr electrons ons of an atom atom can have have the same same set of all four four quantum quantum numbers numbers Reason (R) : An orbital can accommoda accommodate te a maximum of two electrons electrons 105. 105. Asse Assert rtio ionn (A) (A) : 3d 3dxy, 4dxy, 5dxy ......... all are having the same shape i.e., the t he double dumb bell Reason (R) : The The size of orbitals are independent of the principal quantum number 106. 106. Asse Assert rtio ionn (A) (A) :
em
ratio of anode rays is different for different gases
Reason (R) : Proton is the fundamental particle present in gases 107. Asse Asserti rtion on (A) (A) : Y2 measures the electron probability probabili ty density at a point in an atom (R) : Y and Y2 vary as a function of the three co-ordinates ‘r’ (radial part), q and f (angular part) 108. 10 8. Assertion Assertion (A) : Two Two orb orbita itals lswith withsame samevalu valuee of ofl butdifferent valuesof l will have havesamenumber numberofangular angularnodes. nodes. Reason
Reason (R) : Angular wave wave function of an orbital depends upon its l and ml values 109. Assertion (A) (A) : Aufbau principle principle is violated in writing writing electronic electronic configuratio configurationn of Pd Reason (R) : Pd is diamagnetic in nature 110. 110. Assertion Assertion (A) (A) : Spectral Spectral line line would would not be seen seen for a 2p 2px-2py transition Reason (R) : P-orbitals are are degenerate orbitals 111. Assertion Assertion (A) (A) : Energy Energy of orbitals orbitals on on in hydrog hydrogen en atom atom is 1s < 2s 2s = 2p < 3s 3s = 3p = 3d 3d < 4s = 4p 4p = 4d = 4f Reason (R) : The energy of orbitals in hydrogen hydrogen atom is determined by using principal quantum number 112. Assertion (A) : Angular momentum momentum of an electron electron in a orbit is quantized Reason (R) : The electron wave propagating propagating around the nucleus nucleus remains in the same phase, 2 pr = nl 113. 113. Asserti Assertion on (A) : Fine Fine lines lines are obser observed ved in in spectra spectra if an an atom is plac placed ed in a strong strong magne magnetic tic field. field. Reason (R) : Degenerate orbitals split in the presence of magnetic field. 114. 114.
Asserti Assertion on (A) : Spin Spin quantum quantum number number can have have the the value value +1 2 or - 1 2 Reason (R) : (+) Sign Si gn here signifies the wave function.
115. 115.
Asse Assert rtio ionn (A) (A) : The The tran transi siti tion on of of elec electr tron onss n 3 ® n 2 in the atom will emit greater energy than n 4 ® n 3 Reason (R) : n3 and n2 are closer to nucleus than n 4.
Comprehensions type: I. Imag Imagin inee a univ univer erse se in in whic which h the the four four qua quant ntum um num numbe bers rs can can have have the the sam samee poss possib ible le val value uess as in our universe except the angular momentum quantum number ‘l ’ can have integral
values of 0, 1, 2 ……. n instead i nstead of 0, 1, 2 …….. (n-1) and magnetic magneti c quantum number ‘m’ can have integral values of – (l +1) +1) to 0 to (l +1) +1) instead of – l to to 0 to +l .
121. 122. 123.
Electronic Electronic configuratio configurationn of the elemen elementt with atomic atomic number number 25, based based on the above above assumption assumption is 2 6 2 10 5 2 10 2 11 1) 1s 1p 2s 1d 2p 2) 1s 1p 2s 1d 3 9 3 9 1 3) 1s 1p 2s 2p 3s 4) 1s6 1p10 2s6 2p3 Based Based on above above assump assumption tion magne magnetic tic moment moment of the the element element with atomic atomic number number 18 is 1) 24 BM 2) 8 BM 3) zero BM 4) 15 BM Based Based on assum assumptio ptionn after after completio completionn of 3s orbita orbitall electro electronn enters enters into into _____ _______ __ orbita orbitall 1) 3 p 2) 2 d 3) 4 s 4) 1 d -1 1 , 0, + based on the above assumption electronic configuration confi guration of 2 2 the element with atomic number 30 is 1) 1s3 2s3 2p9 3s3 3p9 4s3 2) 1s3 1p15 2s3 1d9 3) 1s9 1p15 2s6 4) 1s3 1p9 2s3 2p9 1d6
124. 124.
If spi spinn quan quantu tum m numb number erss are are
II. II.
Imagi Imagine ne an atom atom made made up of of a prot proton on and and a hyp hypoth othet etic ical al part particl iclee of half half the the mass mass of the the electron but having the same charge as the electron. Bohrs model is applicable and all transition of this hypothetical particle from higher level to ground state is possible.
125.
The largest largest waveleng wavelength th of photon that will will be emitted when hypothetica hypotheticall particle particle jumps jumps to first excited excited level is 18 72 36 2) 3) 5R 5R 5R The The velo veloci city ty of of this this parti particl clee in sec secon ondd Bohr Bohr orbi orbitt is 6 6 1) 2.188´10 m/ m/sec 2) 1.094´10 m/ m/sec 3) 0.547´106 m/ m/sec 1)
126. 127. 127. 128.
The The rad radiu iuss of of Thi Third rd Bohr Bohr orbi orbitt is is 1) 9.522 A0 2) 4.761 A0 3) 2.380 A0 The kineti kineticc energ energyy of of the hy hypothe pothetic tical al partic particle le in firs firstt orbit orbit is 1) –6.8 eV 2) 6.8 eV 3) 27.2 eV
4)
8 R
4) 4.376´106 m/sec 4) 1.587 A0 4) –27.2 eV
III. III.
A single single elec electr tron on atom atom has has nuclea nuclearr charge charge +Ze here here Z is is atomic atomic number number,, e is charge charge.. It requires 47.2 eV to excite the electron from second Bohr orbit to third Bohr orbit
129. 129.
Atom Atomic ic numbe umberr of of the the elem elemen entt is 1) 2 2) 3 3) 4 4) 5 The wav wavele elengt ngthh require requiredd to remov removee electro electronn from from the first first Bohr Bohr orbit orbit in above above data -7 -7 -7 1) 0.22´10 cm cm 2) 1.0´10 cm cm 3) 5.6´10 cm 4) 3.7´10-7 cm The kinetic kinetic energ energyy of of electro electronn in First First Bohr Bohr orbit orbit in above above data data -10 -10 1) 1.962´10 er ergs 2) 3.48´10 er ergs 3) 0.872´10-10 er ergs 4) 5.45´10-10 ergs
130. 131.
Passage - I:
A gas of identical H-like atom has some atoms in the lowest energy energy level A and some atoms in
a particular upper (excited) energy level B and there are no atoms in any other energy level. The atoms of the gas make transition transitio n to a higher energy level by absorbing monochromatic light of photon phot on of energy 2.55 eV. eV. Subsequently, Subsequently, the atoms at oms emit radiation of only six different photon energies. Some of the emitted emit ted photons, have energy ene rgy 2.55 eV. eV. Some have more and some have less le ss than 2.55 eV 132. The initiall initiallyy excite excitedd level level B is 1) 2nd or orbit 2) 3rd or orbit 133. The ionisatio ionisationn energy energy of the gaseous gaseous atom is 1) 13.6 eV 2) 14.4 eV 134. The minimu minimum m energy energy of the emitte emittedd photon photon is 1) 2.7 eV 2) 2.0 eV
3) 4th or orbit
4) 5th orbit
3) 27.2 eV
4) 54.4 eV
3) 0.66 eV
4) 0.54 eV
Passage - II:
In the photoelectric effect, an incoming photon br i ngs ng s a d ef i n i te qu an t i t y of ener en ergy, gy, hv. It collides with an electron close to the surface of the metal target, and transfers its energy to it. The difference between the work function, f, and the energy hv appears as the kinetic energy of the ejected electron. The minimum potential at which the plate photoelectric current becomes zero is called the stopping potential potential.. If V0 is the stopping potential, potential, then eV0 = h(v – v 0) 0
135. Ligh Lightt of wave wavelen length gth 4000 4000 A is incident on a metal whose work function is 2 eV. eV. Then the maximum possibl possiblee kineti kineticc energy energy of the photoe photoelec lectron tron is 1) 3.09 eV 2) 1.9 eV 3) 1.09 eV 4) None of these 136. The threshold threshold freque frequency ncy for for emitting photoele photoelectrons ctrons from from a metal surface surface is 5 ´ 1014 s –1. Which of the following could be the frequency of radiation to produce photoelectrons having twice the kinetic energy of those produced by the rradiation adiation of frequency fr equency 1015 sec –1. 1) 2.15 ´ 1014 s –1 2) 3.70 ´ 1013 s –1 3) 4.11 ´ 1014 s –1 4) 15 ´ 1014 s –1 137. If one photon photon has 25 eV energy energy and the the work function of of the material is 7 eV, eV, then value of the stopping stopping pote potent ntia iall will will be 1) 32 V 2) 18 V 3) 3.3 V 4) Zero Passage – I :
According to Planck’s quantum theory of radiation, radiati on, the radiant energy is emitted or absorbed discontinuously in the t he form of quanta. The energy of a quantum is given by E = hv, where ‘v’ is the frequency of radiation. Moreover, a body can emit or absorb energy only in an integral multiple of quantum. 138. Planck’s Planck’s quantum theory theory of radiation radiation favours the following nature nature of electromag electromagnetic netic radiation 1) Particle nature 2) Wave nature 3) Dual nature 4) None of these 0
139. The energy energy associated associated with with one photon of waveleng wavelength th 3000 A is 1) 5.42 ´ 10 –19 J 2) 6.63 ´ 10 –19 J 3) 3.73 ´ 10 –16 J 4) 3.73 ´ 10 –19 J 140. Which of the following is not the correct representation of Einstein’s Einstein’s photoelectric photoelectric equation? 1 2 1 2 1 2 1 2 1) mv = h ( v + v0 ) 2) hv = hv0 + mv 3) hv = W + mv 4) mv = h ( v - v0 ) 2 2 2 2 Passage – II :
The properties of electrons indicate that they have a dual nature, i.e., they behave both as particle and as wave. de-Broglie suggested that every object which possesses mass and velocity velocit y behaves both as a particle and as a wave. According to de-Broglie, the wavelength l of a particle of mass ‘m’, moving with a velocity ‘v’ is given by l = h/mv. The The dual nature of electron further gets support by Heisenberg’s Heisenberg’s uncertainty uncertainty principle which states that t hat it is not possible to determine simultaneously and accurately the position and momentum of a moving electron or some other microscopic particle. h
According to Heisenberg, D x Dp ³
, where Dx and D p respectively respectively represent represent the uncertainties uncertainties 4p involved in the simultaneous determination of position and momentum of a moving particle
144. The de-Broglie de-Broglie wavelength wavelength of a cricket cricket ball of mass mass 0.2 kg moving with a velocity velocity of of 30 ms –1 would be 1) 1.8 ´ 10 –34 m 2) 3.6 ´ 10 –32 m 3) 2.2 ´ 10 –34 m 4) 1.1 ´ 10 –34 m 145. An electro electronn can be loca located ted with with an error error equal equal to 10 –10 m. What is the uncertainty in its momentum? momentu m? 1) 5.28 ´ 10 –25 kg ms –1 2) 5.5 ´ 10 –26 kg ms –1 3) 3.34 ´ 10 –14 kg ms –1 4) 6.63 ´ 10 –27 kg ms –1 146. If the uncertainty in the position and momentum momentum for an electron are equal, then the uncertainty uncertainty in its velocity is 1)
h
2)
p
h
3)
2p
1
h
m
2p
4)
1
h
2m p
Passage – I :
In 1908, W. Ritz introduced his combination principle, which is virtually virtuall y a generalization of Balmer formula. In its simplest form the principle states that the wave number of any spectral spectral line may be repre represe sente ntedd as the combi combina natio tionn of two terms, terms, one of which which is const constan antt and and the other other varia variable ble throug throughh out each spectral series. R n = = 2 x
-
R y2
; x and y integers for H-atom. The later on theories t heories have modified the above
princip principle le as for H-atom. H-atom.
ì1
1ü
î n1
n22
n = R H í
2
ý
R H is Rydberg number = 109,677.76 cm –1 and n1 and n2 are lower and higher energy levels of the th e H-atom 147. What What transitio transitionn H-spect H-spectrum rum would would have have the same same l as the Balmer transition n = 4 to n = 2 of He+ spectrum? 1) 2 ®1 2) 3 ® 1 3) 4 ® 1 4) 5 ® 1 + 148. The wavelen wavelength gth of radiation radiation of longest longest transition transition in Lyma Lymann series series of He ion is 1) 22.8 nm 2) 32.2 nm 3) 40 nm 4) 48 nm
149. 149. If the the sho short rtes estt l of H-atom in Balmer series is l1, the longest l ongest l in Lyman Lyman series is is 1) 0.14 l1
Passage- I
2) 0.33 l1
3) 0.44 l1
4) 0.66 l1
A hydrogen - like atom (atomic number number z) is in a higher excited state of of quantum numbe ‘n’. This excited atom can make a transition tr ansition to the first fi rst excited state by successively emitting two photons of energies 10.2 eV and 17.00 eV respectively. respectively. Alternatively, Alternatively, the atom from the same excited state can make a transition transiti on to the second excited state stat e by emitting two photons phot ons of energy 4.25 eV and 5.95 eV respectively. 150. 150. The The val value ue of n is 1) 8 2) 6 3) 5 4) 4 151. The The ato atomi micc numb number er Z is 1) 1 2) 2 3) 3 4) 4 Passage - I:
A formula analogous to the Rydberg formula applies appl ies to the series of spectral lines lin es which arise from transitions from higher energy levels to the lower energy level of hydrogen atom. A muonic hydrogen ion is like a hydrogen atom in which the electron is replaced by a heavier partica particall the muon. muon. The mass mass of the muon muon is 207 times times the mass mass of an electr electron on while while charg chargee the double double that the electron (assume charge of proton is same) 152. Radius Radius of first first Bohr Bohr orbit of muonic muonic hyd hydroge rogenn ion is 0.529 0 0.529 0 0.529 0 A A A 2) 3) 207 414 828 153. Ionizati Ionization on energy energy of of muonic muonic hydrog hydrogen en ion is 1) 13.6 ´ 20 207 eV 2) 13.6 ´ 41 414 eV 3) 13.6 ´ 82 828 eV 154. 154. Dist Distan ance ce bet betwe ween en 1st and 3rd Bohr orbit of muonic hydrogen hydrogen ion wil be
1)
1)
0.529 ´8 A0 207
2)
0.529 ´8 A0 414
3)
0.529 ´5 A0 207
4) 0.529 ´ 828 A0 4) 13.6 ´ 3312 eV
4)
0.529 ´8 A0 828
One or more than one correct type questions :
160. Which of the following followingss can be concluded concluded correc correctly tly from the solution solution of schroding schrodinger er equation equation ? 1) For all orbitals, the radial wave-function (y ) approaches to zero as r (distance from nucleus) approaches infinity. 2) The radial probability density (y 2 ) for 1s orbital is maximum at nucleus. 3) The radial distribution function ( 4p r 2 dr y 2 ) for 1s orbital is minimum minimum at nucleus. nucleus. 4) In plot of radial wave function (y ) ,y changes its sign at nodes. 161. When photons of of energy energy 4.25 eV eV strike the surface surface of a metal metal A, A, the ejected photo photo electrons have have maximum kenetic energy TA (expressed in eV) and de Broglie wavelength lA. The maximum kinetic energy of photo electrons liberated from another matal ‘B’ by photons of energy 4.20 V is TB = TA – 1.5 (expressed in eV). If the de Broglie wavelength of these photo electrons is
lB = 2lA then
1) Work function of A is 2.25 eV 3) TA = 2 eV
2) Work function of B is 4.20 eV 4) TB = 2.50 eV
162. In a photoelec photoelectric tric experiment, experiment, the stopping stopping potential potential is plotted plotted against against
1
of incident radiation for two
different metals, the curve is like as shown in the t he fig. Predict which of the following statements are coorect :
1) Slope of the curves curves for both the metals is 1. 1.242 242 ´ 10 –6 Jm coulumb –1 2) When an electromagnetic radiation of wavelength 100 nm strikes the two metals separately s eparately,, the stopping potential for metal I is 12.18 V 3) The stopping potential for metal I is more than that of of metal II, if both the metals are exposed to electromagnetic electromagnetic radiation of wavelength wavelength 200 nm seperately 4) The stopping potential for metal met al II is more than that of metal I, if both the metals are exposed to electromagnetic electromagnetic radiation of wavelength wavelength 200 nm seperately 163. Consid Consider er follow following ing statem statements ents and select select the the corre correct ct state statemen ments ts 1) Light Light waves waves were considere consideredd electroma electromagneti gneticc in nature nature 2) In vacuum, vacuum, all types types of electromagnetic electromagnetic radiation radiation regardle regardless ss of their wavelength, wavelength, travel travel at the same 8 -1 speed, i.e., 3 ´10 ms . 3) The ideal body body which emits emits and absorbs absorbs all frequencies, frequencies, is called a black body body.. 4) Quantu Quantum m is also also calle calledd phot photon. on. 164. Which Which of the following following pairs pairs have have iden identica ticall values values of magne magnetic tic mome moment nt +2 + +2 +2 4+ 2+ 1) Zn , Cu 2) Co , Ni 3) Mn , Co 4) Mg+2, Sc+ 165. Which Which of the follow following ing statem statement entss are are (is) (is) corr correc ectt 1) Electrons Electrons in motion behave behavess as if they they were were waves waves 2) s-orbi s-orbital tal is non non dire directi ction onal al 3) An orbital orbital can accommo accommodate date a maximum maximum of two electr electrons ons with paralle parallell spins 4) The energie energiess of the various various sub shells shells in the same same shell shell are in the order order s > p > d > f 166. The nucleus nucleus of an atom is located located at x = y = z = 0. If the probability probability of of finding an ‘s’ orbital orbital electron in a tiny volume around ar ound x = a, y = z = 0 is 1. 1.00 ´ 10 –5, choose the correct statement(s) regarding the proba probabili bility ty of e – 1) The probability of find finding ing the electron in the t he same-sized volume around x = z = 0, y = a is the same i.e. 1 ´ 10 –5 2) The probability probabili ty of finding the electron elect ron in the same-sized same-siz ed volume around x = y = 0, z = a is zero 3) The probability at the second site if the electron were in a p z orbital is zero
4) The probability at the second site if the t he electron were in a p z orbital is the same i.e. 1.0 ´ 10 –5. 167. Choose the the correct correct statement(s) statement(s) regarding regarding Bohr-Somm Bohr-Sommerfeld’ erfeld’ss model. 1) All paths around the nucleus are elliptical elli ptical 2) When an electron revolves around the nucleus following fol lowing circular path, pat h, only angle of rotation is changed 3) When an electron revolves around the nucleus following elliptical path, both the angle of rotation and the distance from the nucleus n ucleus are changed 4) For an elliptical path, k < n æ 1 ç 168. If there there were were three three poss possible ible values values ççè- , 0, 2
1 ÷ö ÷ for the spin magnetic quantum number (m ). Which of s 2 ÷ø the following statement(s) is/are correct regarding a hypothetical hypothetical periodic table based on this condition? 1) First period would have only 2 vertical columns 2) Second period would have 12 elements 3) Periodic table would contain 27 groups 4) Third period would have 12 elements
169. Select Select the the wrong wrong stateme statements nts : 1) If the shortest wave length of H-atom in Lyman series is ‘x’, then the longest wave length in Balmer 9 x series of He+ ion is 5 2) When an electron jumps from 4 th excited state to ground state, maximum no. of protons that may be emitted are 4 3) Number of nodal planes and radial nodes in 5dx 2 – y2 orbital are 2 and 1 spectively 4) All four quantam number are obtained from f rom Schrodinger wave equation even applied on atom 170. Choose Choose the correct correct statement statement among among the following following : 1) Radial distribution distribution function (Y2 4pr 2) give probability at a particular distance along one chosen direction 2) ‘xz’ plane acts as nodal plane for 3P x orbital 3) For ‘s’ orbitals wave function is independent of q and f 4) ‘2p’ orbital with quantum numbers n = 2, l = 1, m = 0, also shows angular dependence 171. Accord According ing to Bohr’ Bohr’ss theory theory,, 1) When the atom gets the required energy from the outside, electrons jump jum p from lower orbits to higher orbits and remain there 2) When the atom gets the required energy from outside, electrons jump from lower orbits to higher orbits and remain there for very short intervals of time and return back to the lower orbit, radiating energy 3) Angular Angular momentum of the electron is proportional to its i ts quantum number 4) Angular Angular momentum of the electron is independent independent of its quantum number 172. Choose the correct correct statement(s statement(s)) regarding regarding the photoelectric photoelectric effect effect 1) No electrons are ejected, regardless of the intensity int ensity of the radiation, unless the th e frequency equal and exceeds a thereshould value characteristic of the metal 2) The kinetic energy of the ejected electrons varies linearly with the frequency of the incident radiation radiat ion and its intensity 3) Even at low intensities, int ensities, electrons are ejected immediately if the frequency is above the threshold value 4) An intense and a weak beam of monochromatic monochromat ic radiations differ in i n having number of photons and not in the energy of photons
173. Mark Mark out the the correc correctt stateme statement( nt(s) s) 1) Electrons within a subshell for which l > 0 mean the relatively greater electrostatic repulsion repulsi on between two electrons in the same orbital within a subshell as compared with occupancy of two orbitals having different m1 values 2) Electrons in singly occupied orbitals tend to have their spins in the same directon dir ecton so as to maximise the net magnetic moment 3) In the ground state, an atom adopts a configuration configurati on with the greatest number of unpaired unpaire d electrons 4) Electrons in different orbitals with wit h parallel spins show mutual attraction, so the electron-nucleus interaction is improved 174. Which Which of the the following following statements statements is/are is/are correct? correct? 1) For all values of ‘n’ the p-orbitals p-orbi tals have the same shape, but the overall size increases i ncreases as ‘n’ increases, for a given atom 2) The fact that there is a particular direction, di rection, along which each p-orbital p-orbi tal has maximum e-densi e-density ty,, plays an important role in determining molecular geometries 3) The charge cloud of a single electron in i n 2Px atomic orbital consists consist s of two lobes of e-density 4) The very fact that an e – is present in both the lobes at equal times, tim es, and the fact that in order to move from one lobe to another, it MUST cross the node, implies, there is at least some probability of finding an e – in the node 175. In a hydro hydrogen gen like like sample sample elec electron tron is in 2nd excited state, the Binding energy of 4th state of this sample is 13.6 eV then 1) A 24.17 eV photon can set free the electron el ectron from the second excited state of this sample 2) 3 different types of photon will be observed if electrons make transition up to t o ground state from the second excited state 3) If 23 eV photon is used then K.E of the ejected electron is 1 eV 4) 2nd line of Balmer series of this sample has same energy value value as 1st excitaation energy of H-atoms 176. Identify Identify the correc correctt statement( statement(s) s) among among the followin followingg : 1) If Aufbau rule is not followed then chromium will wi ll still remain remain in d-block 2) If there are three possible values val ues for spin quantum numbers number s then chromium would have been lying in s-block 3) If Hund’s Hund’s rule of maximum multiplicity is not followed foll owed then magnetic moment of chromium would be zero 4) If Hund’s Hund’s rule of maximum multiplicity multipl icity is not followed then Cr 3+ (aq) ion would be colourless 177. The energy energy of an electron in the first Bohr orbit of H-atom –13.6 –13.6 eV; eV; then which of the following statement(s) is/are correc correctt for He+? 1) The energy of electron in second Bohr orbit is –13.6 eV 2) The K.E of electron in the first orbit is 54.46 ev 3) The K.E of electron in secondary orbit is 13.6 ev 4) The speed of electron in the second orbit is 2.19 ´ 10 106 m/sec Matching type questions : 181. Match the following Type – I
(A) (B) (C) (D)
Distance of maximum probability of 1s electron Radial node of 2s electron is Radius of 2nd orbit in He+ io ion is rd +2 Radius of 3 orbit in Li io ion is
Type – II
(p) (q) (r) (s)
1.1 A0 1.06 A0 1.59 A0 0.53 A0
182.
List – I
a) Emission spectrum b) Absorp Absorption tion spectru spectrum m c) Band spectrum d) Line spectrum
List – II
p) Cold nitrogen gas q) Excite Excitedd atomic atomic hydro hydroge genn r) Very hot carbon dioxide s) Neon gas at room temperature
183. Matc Matchh the the foll follow owing ing : List – I
List – II
a) Magnetic moment of an atom or ion b) Radial Radial node node c) Hund’s rule d) Orbital angular momentum of electron
p) Principal Q.N. q) Azimth Azimthal al Q.N. Q.N. r) Magnetic Q.N s) Sp Spin Q.N.
184. Match Match the follow following ing List List – I with List List – II List – I (Species)
a) Hydrogen atom b) Nitroge Nitrogenn atom atom c) Li2+ io ion d) Helium atom 185. Column – I a) Magnetic movement b) split splittin tingg of spect spectra rall lines lines in magne magnetic tic field field c) number of spherical nodes d) fine line spectra
List – II (Factors affecting the energy)
p) Principal quantum numer q)Azim Azimut utha hall quan quantu tum m numb number er r) Exchange energy s) Symmetry Column – II
p) principal quantum number q)Azim Azimut utha hall quan quantu tum m numb number er r) Magnetic quantum number s) Spin quantum number
186. n ® orbit no; z ® at no; r n, z ® radius Vn, z ® velocity; Tn, z period of revolution K n, z ® kinetic energy of the electron Colu Column mn – I (of (of sing single le elec electr tron on spec specie ies) s)
Time
®
Colu Colum mn – II (rat (ratio io))
a) r 2, 1 : r 1, 2
p) 9 : 1
b) V1, 3 : V3, 1
q) 8 : 1
c) T1, 2 : T2, 1
r) 16 : 1
d) K 1, 2 : K 2, 1
s) 1 : 32
187. Match the entries entries in Column Column – I with the correctly correctly related quantum quantum number(s) number(s) in Column Column – II. List – I
List – II
a) Orbit Orbital al ang angular ular moment momentum um of of the the elec electron tron in a hydro hydroge gennlike atomic orbital b) A hydro hydroge gen-l n-like ike one-el one-elec ectro tronn wave wave functio functionn obeyi obeying ng Pauli Pauli principle c) Shape, Shape, size and orientatio orientationn of hydroge hydrogen-like n-like atomic atomic orbitals orbitals d) Probability density of electron at the nucleus in hydrogen-like hydrogen-like atom 188.C 188. Column - I (Q (Quantum nu numbers) A) n
p) Princ Principa ipall qun qunatu atum m numb number er q)Azim Azimut utha hall quna qunatu tum m numb number er r) Magne Magnetic tic quan quantum tum numbe number r s) Electron spin quantum quantum number number
Column - II (R (Relation) p) Stark effect
B)
q) Schrodinger's equation
C) m
r) Bohr's atomic model
D) s
s) Pauli's exclusivity t) Auf Bau sequencing
189. 190. Numericals:
191. 191.
In whic whichh quan quantum tum level level doe doess the the elec electro tronn jumps jumps in He He+ ion to ground state if it is given an energy corresponding corresponding to 99% of the the ionizatio ionizationn potentia potentiall of He He+ ion.
192.
When a certain certain metal was irradiated irradiated with light having having a frequenc frequencyy of 3.0 3.0´1016 sec-1. The photo electrons emitted had twice the kinetic energy as did photoelectrons emitted when the same metal was irradiated with wit h light having a frequency of 2.0´1016 sec-1. The threshold frequency of metal (in 1016 sec-1) is
193.
Given Given ioniza ionizatio tionn pote potenti ntial al of of hyd hydrog rogen en atom atom is 2.0´10-18 J Plank’s Plank’s constant is 6.0 ´10-34 J.sec. J.sec. The 12 frequency Hb line in Balmer series is in the values of (10 Hz) is
194.
The radiu radiuss of the the orbit orbit in hydr hydroge ogenn atom is 0.8464 0.8464 nm. nm. The velocity velocity of electro electronn in this this orbit orbit (in the the 3 order of 10 m/sec) is
195. The velocity of electron is a certain Bohr’s Bohr’s orbit of hydrogen hydrogen atom bears in the ratio ratio 1 : 275 to the velocity of light. The qunatum number (n) of orbit is 0
196. The wave wave length length of a line in Balmer Balmer series series of hydro hydrogen gen atom is 4814 4814 A . In which orbit deexitation takes place place 0
197. The debroglie debroglie wave wave length length of an electron in a certain orbit of hydrogen hydrogen atom is 13.3 13.3 A . So the no. of waves present in an orbit is 198.
Give the numb number er of angu angular lar node node of orbital orbital belon belongs gs to subs subshell hell for for which which minimum minimum value value of magnet magnetic ic quatum number is –2. 199. What What will be the the numbe numberr of lines lines corres correspon pondin dingg to lymen lymen seri series es when when an elec electron tron is is in 3rd excit excited ed state of hydrogen atom. 200. In a sing single le hydro hydroge genn atom, atom, the electr electron on is excited excited to its its 6th orbit. The maximum no.of distinct lines possible, possible, when when it comes comes to the ground ground state is : 1 201. 201. For the the hydro drogen atom, tom, En = 2 RH n
Where, R H = 2.178 x 10 –18 J Assuming that the electrons in other shells exert no effect, find the minimum no.of Z(atomic no.) at which a transition from the second energy level to the first results in the emission of an X–ray X–ray.. Given that the lowest l owest energy rays have l = 4 ´ 10 -8 m .