Atomic Structure-Objective Questions

Following IIT JEE Entrance Multiple choice objective type questions and answers will help you in Maths, Physics and Chemistry 2014 examinations :

1.Davisson and Germer gave an experimental evidence for

wave nature of electron particle nature of electron particle nature of light wave nature of light ANSWER : : wave nature of light 2.The velocity of a photon is

dependent on its wavelength dependent on its source equal to cube of its amplitude independent of its wavelength ANSWER : : independent of its wavelength 3.The screening effect of d-electrons is

equal to that of f-electron equal to that of d-electron less than that of s-electron more than that of s-electron ANSWER : : more than that of s- electron 4.The exchange of particles considered responsible for keeping the nucleons together are

meson electron positron neutron ANSWER : : meson 5.The element with maximum number of electrons in the valence shell has atomic number

15 3

9 2 ANSWER : : 2

6.Bohrs concept of the orbit in an atom was contradicted by

de Broglie relationship Uncertainty principle Plancks hypothesis Hunds rule ANSWER : : Uncertainty principle 7.The statement that the electron occupies available orbital singly before pairing occurs is called

Einstein principle Rutherford hypothesis Paulis exclusion principle Hunds rule ANSWER : : Hunds rule 8.The maximum number of molecules are in:

52 gram of nitrogen peroxide 48 gram of ethyl alcohol 36 gram of water 14 gram of carbon dioxide ANSWER : : 36 gram of water 9.The unrelated member of the following group is

He ion neutron proton cyclotron ANSWER : : c yclotron 10.Two electrons occupying the same orbital are distinguished by

magnetic quantum number azimuthal quantum number principal quantum number spin quantum number ANSWER : : spin quantum number


11.The yellow colour imparted by sodium to flame is due to

the emission of excess of energy in the visible region its sublimation to give yellow vapours its low ionisation energy its photosensitivity ANSWER : : the emission of excess of energy in the visible region 12.Which of the following atoms has a nonspherical outermost orbital.

H Li Be B ANSWER : : B 13.In Lyman series an electron jumps from higher energy level to

K energy level M energy level N energy level L energy level ANSWER : : K energy level 14.A quantum of energy is

inversely proportional to wavelength of radiation directly proportional to velocity of radiation

directly proportional to wavelength of radiation a constant quantity ANSWER : : inversely proportional to wavelength of radiation 15.The photoelectric emission of electron from metal surface starts only when the incident light has a certain minimum

wavelength velocity frequency acceleration ANSWER : : frequency 16.Charge on an electron was shown by

J.J. Thomson Mirchoff Ohm M. Planck ANSWER : : J.J. Thomson 17.A mole of electrons is the same as

ampere-second one faraday curie ANSWER : : faraday 18.The wavelength of an electron

is equal to that of light remains constant with velocity decreases with an increasing velocity increases with an decreasing velocity ANSWER : : decreases with an increasing velocity 19.No two electrons in an atom can have the same values of all four quantum numbers according to

Hunds rules Flemming rule Paulis exclusion principle Bohr theory ANSWER : : Paulis exclusion principle 20.The number of unpaired electrons in fluorine atoms is/are

4 2 1 0 ANSWER : : 1


21.Subsidiary quantum number of the electron in the outermost shell of Li atom is

0 1 4 5 ANSWER : : 0 22.According to de-Broglie

a moving proton possesses wave character a moving electron possesses wave character light possess particle character all moving particles possess wave character ANSWER : : all moving particles possess wave character 23.When the electron is excited from K level to M level we get

?�rays

cathode rays continuous spectra absorption spectra ANSWER : : absorption spectra 24.Mass of positron is the same to that of

proton meson electron neutron ANSWER : : electron 25.An alpha particle consists of

two protons and two neutrons two mesons two electrons helium atoms ANSWER : : two protons and two neutrons 26.How many electrons can fit into the sub-shell for which n = 3 and l = 1?

16 5 24 6 ANSWER : : 6 27.In the case of atomic spectrum of hydrogen which series of lines lie in the visible region?

Balmer Paschen Pfund None of these ANSWER : : Paschen 28.The application of quantum mechanics to atomic structure is based largely on the work done b y

Einstein Germer Schrodinger Davison ANSWER : : Schrodinger 29.Electromagnetic radiation with minimum wavelength is

ultra violet radiowaves X-rays infrared ANSWER : : ultra violet


1.The filling of electrons in different orbitals of an atom in increasing order of their energy is called

Aufbau principle Joules statement Uncertainty principle Paulis exclusion principle ANSWER : : Aufbau principle 2.The interrelationship between matter and energy was given by

Rutherford Joule de Broglie Einstein ANSWER : : Einstein 3.The relationship between energy of a radiation and its frequency was given by

Planck Rutherford

Einstein Joule ANSWER : : Einstein 4.The orbitals with maximum number of possible orientation is:

s d f p ANSWER : : f 5.The atomic mass of an element is 16.4. It consists of two isotopes having mass number 16 and 18. The ratio of isotopes in the element is:

2:1 1:2 1:4 4:1 ANSWER : : 4:1


6.The line spectrum observed when electron jumps from higher level into L level is known as

Balmer series Pfund series Brackett series Hydrogen series ANSWER : : Balmer series 7.In hydrogen atom the energy of an electron is determined by quantum number/s

n n and l n, l and m

n, l, m and s. ANSWER : : n 8.The number of electrons with quantum numbers n = 3 and l = 2 in chromium is

8 6 5 7. ANSWER : : 5 9.In an atom of hydrogen, which of the following orbitals has the lowest energy for an electron present in it?

3r 2p 4p 2s ANSWER : : 2p 10.Which of the following has non-spherical shell of electron?

He B Be Li. ANSWER : : B


11.Which of the following sub-shells is not permitted?

3f 4d 3s 4g. ANSWER : : 4g.

12.The number of neutrons in the deuterium atom is

16 3 1 0 ANSWER : : 1 13.The total number of neutrons in dipositive zinc ion with mass number 70 is

40 48 33 16 ANSWER : : 40 14.The number of unpaired electrons in the ground state of chromium is

1 6 7 2 ANSWER : : 6 15.The false statement about the electron is:

It has a particle nature It has a dual nature It gives out energy while moving in orbits Its motion is affected by electric field ANSWER : : It gives out energy while moving in orbits


16.The spectra given by the transition of an electron from K level to N level is

rays

continuous absorption emission ANSWER : : absorption 17.The atomic mass of an element is 19. The second shell of its atom contains 7 electrons. The number of protons in its nucleus is

13 9 11 8 ANSWER : : 9 18.The number of vacant orbitals in the atom of an element with Z = 14 is

1 6 9 3 ANSWER : : 6 19.How many electrons in an atom can have n = 3, l = 2 and m = +2?

10 8 6 2. ANSWER : : 2. 20.Nucleons are

protons and electrons electrons and mesons protons, electrons and neutrons protons and neutrons ANSWER : : protons and neutrons


21.The quantum number predicting the size as well as the energy of the atomic orbital is:

principal quantum number azimuthal quantum number magnetic quantum number spin quantum number ANSWER : : principal quantum number 22.The nitrogen atom has 7 protons a nd 7 electrons. The nitride ion will have

7 protons and 7 electrons 4 protons and 10 electrons 10 protons and 7 electrons 10 electrons and 7 protons ANSWER : : 10 electrons and 7 protons 23.Radial part of the wave function depends on quantum numbers

n and s l and m l and s n and l. ANSWER : : n and l. 24.Avogadros number of helium atoms weigh

1.5g 3.0g 7.0g 4.0g ANSWER : : 4.0g 25.Method to determine atomic numbers was devised by

J.J. Thomson H.G..J. Moseley

R. Milikan ` Rutherford. ANSWER : : H.G..J. Moseley


26.The maximum number of electrons that can be accommodated by an atom in g �sub-energy level are

20 25 18 12 ANSWER : : 18 27.The number of spherical nodes in 3p subshell is

Three Two One Zero. ANSWER : : One 28.The (n and l) value for 4f orbital is

2 7 8 3 ANSWER : : 7 29.The possible values of l for an s orbital are

-1, +1 0 to 2 -2 and +1 0

ANSWER : : 0


1.The energy of an electron in the first Bohr orbit of H atom is- 13.6 eV. The possible value of the excited state for electron in Bohr orbits of hydrogen is

- 1.51 eV - 4.21 eV - 6.8 eV + 6.8 eV. ANSWER : : - 1.51 eV 2.The ratio of specific charge of an electron to that of a proton is

1:1 1837:1 1:1837 2:1. ANSWER : : 1837:1 3.According to Bohrs atomic model

Electron in an atom of hydrogen can have only certain values of angular momentum Electrons have particle as well wave character Atomic spectrum of an element should contain only five lines All the above statements are incorrect. ANSWER : : Electron in an atom of hydrogen can have only certain values of angular momentum 4.The maximum number of electrons in p-orbital with n = 6, m = 0 is

2 6 10 14. ANSWER : : 2

5.Which combinations of quantum number n, l, m, s for the electron in an atom does not provide a permissible solution of the wave equation?

3, 2, -2, 1/2 3, 3, 1, -1/2 3, 2, 1, 1/2 3, 1, 1,-1/2. ANSWER : : 3, 3, 1, - 1/2


6.Rutherfords model of the atom accounts for the

Scattering of alpha particles by metal foils Stability of the electron orbit Stability of the atom Line spectra of light elements. ANSWER : : Scattering of alpha particles by metal foils 7.How many electrons in an atom can have quantum numbers n = 3, l = 2, m = +2, s = +1/2?

5 3 1 9. ANSWER : : 1 8.When an atom is in a magnetic field, the possible number of orientations for an orbital of azimuthal quantum number 3 is

Three One Five Seven. ANSWER : : Seven. 9.How many electrons in calcium have l = 0?

6 8 10 12. ANSWER : : 8 10.According to Aufbau principle, the 19th electron in an atom goes into the

4s-orbital 3d-orbital 4p-orbital 3p-orbital. ANSWER : : 4s-orbital


11.The hydrogen atoms are excited to the stationary state designated by the principal quantum number, n = 3. The spectral lines emitted by h ydrogen atoms, as explained by Bohrs theory will be

1 2 3 4. ANSWER : : 3 12.In a multi-electron atom the energy of the electron in a particular orbital is determined by

n only l only n and l n, l and m. ANSWER : : n and l 13.The ionization energy of hydrogen atom is 13.6 eV. The third ionization energy of lithium would be

13.6 eV

27.2 eV 40.8 eV 122.4 eV. ANSWER : : 122.4 eV. 14.An atom has 35 nucleons and has atomic number equal to 17. The number of electrons with n = 2, m = 0 in it is

2 4 6 3. ANSWER : : 4 15.The number of orbitals in the fourth energy level is

4 16 32 9. ANSWER : : 16


16.The charge to mass ratio of ?-particles is approximately��. The charge to mass ratio of protons

twice half four times six times ANSWER : : half 17.The wavelength of the radio-waves having frequency 3 MHz would be

100 m 300 m

100 nm 300 nm. ANSWER : : 100 m 18.The maximum number of electrons with clockwise spin that can be accommodated in a �-subshell its

14 7 5 10. ANSWER : : 7 19.The energy of hydrogen atom in its ground state is - 13.6 eV. The energy of the level corresponding to the quantum number n = 5 is

- 0.54 eV - 5.40 eV - 0.85 eV - 2.72 eV. ANSWER : : - 0.54 eV 20.The ratio of the mass of the proton to the mass of the electron is nearly

2000 4801 1840 8140. ANSWER : : 1840


21.The maximum number of electrons that can be accommodated in fifth energy level is

10 25 50

32 ANSWER : : 50 22.In chromium atom, in ground state, the number of occupied orbitals is

14 15 7 12 ANSWER : : 15 23.The first use of quantum theory to explain the structure of atom was made by

Heisenberg Bohr Planck de Broglie. ANSWER : : Bohr 24.Which of the following metals is most likely to exhibit photoelectric effect?

Gold Platinum Chromium Caesium. ANSWER : : Caesium. 25.The wavelength of a spectral line for electron transition in an atom is inversely proportional to

Velocity of electron Number of electrons undergoing transition The difference of energy between energy levels involved in the transition None of the above is correct. ANSWER : : The difference of energy between energy levels involved in the transition


26.The number of subshells in the fifth energy level is

4 11 9 5. ANSWER : : 5. 27.Which of the following does not characterize X-rays?

The radiation can ionise the gas It causes ZnS to fluoresce Deflected by electric and magnetic field Have wavelength shorter than ultra-violet rays. ANSWER : : Deflected by electric and magnetic field 28.Neutrons were discovered by

J.J. Thomson Rutherford James Chadwick G.T. Seabery. ANSWER : : James Chadwick

Atomic Structure-Objective Questions

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