Structure Of Atom - MCQ Test
All questions are compulsory. Read the questions carefully before attempting. Passing criteria: 40%
- 1.
The density of dots in a region represents the probability density of finding electrons in the region.The probability density plots of 1s and 2s orbitals are given in Fig. On the basis of below diagram which of the following statements is incorrect?- A.
1s and 2s orbitals are spherical in shape.
- B.
The probability of finding the electron is maximum near the nucleus.
- C.
The probability of finding the electron at a given distance is equal in all directions.
- D.
The probability density of electrons for 2s orbital decreases uniformly as distance from the nucleus increases.
- 2.Which of the following statements about the electron is incorrect?
- A.
It is a negatively charged particle.
- B.
The mass of electron is equal to the mass of neutron.
- C.
It is a basic constituent of all atoms.
- D.
It is a constituent of cathode rays.
- 3.Two atoms are said to be isobars if:
- A.
They have same atomic number but different mass number.
- B.
They have same number of electrons but different number of neutrons.
- C.
They have same number of neutrons but different number of electrons.
- D.
Sum of the number of protons and neutrons is same but the number ofprotons is different.
- 4.Which of the following is responsible to rule out the existence of definite paths or trajectories of electrons?
- A.
Pauli’s exclusion principle.
- B.
Heisenberg’s uncertainty principle.
- C.
Hund’s rule of maximum multiplicity.
- D.
Aufbau principle.
- 5.Total number of orbitals associated with third shell will be __________.
- A.
2
- B.
4
- C.
9
- D.
3
- 6.Orbital angular momentum depends on __________.
- A.
L
- B.
N and l
- C.
N and m
- D.
M and s
- 7.If travelling at same speeds, which of the following matter waves have the shortest wavelength?
- A.
Electron
- B.
Alpha particle (He 2+)
- C.
Neutron
- D.
Proton
- 8.Lyman series of spectral lines appear in the ________________ portion of spectrum.
- A.
UV
- B.
Infra red
- C.
Visible
- D.
Microwave
- 9.The correct sequence of sub-shells according to AUFBAU principle follows:
- A.
3s, 3p, 4s, 3d, 4p
- B.
3s, 3p, 3d, 4s, 4p
- C.
3s, 3p, 4s, 4p, 3d
- D.
3s, 3p, 3d, 4p, 4s
- 10.The frequency of line spectrum is 5.09 × 1014 Hz. Its wavelength (in Nano meter) will be: [Given: Speed of light, c = 3 × 108 m/s]
- A.
510 nm
- B.
420 nm
- C.
589 nm
- D.
622 nm
- 11.The electronic configuration of atom is [Ne] 3s2 3p3 .The symbol of the element is:
- A.
S
- B.
P
- C.
Cl
- D.
Si
- 12.The wavelengths of two photons are 2000 AO and 4000 AO respectively. What is the ratio of their energies?
- A.
1/4
- B.
4
- C.
1/2
- D.
2
- 13.The number of electrons in one molecule of CO2 are:
- A.
22
- B.
44
- C.
66
- D.
88
- 14.Which of the following postulates does not belong to Bohr's model of the atom?
- A.
Angular momentum is an integral multiple of h/ 2π
- B.
The electron stationed in the orbit is stable.
- C.
The path of an electron is circular.
- D.
The change in the energy levels of electrons is continuous.
- 15.
The presence of one electron in each of the three 2p sub-shell of nitrogen is explained by:
- A.
Uncertainty principle
- B.
Hund's rule
- C.
Pauli's exclusion principle
- D.
Aufbau principle
- 16.To give designation to an orbital (read orbital, not sub-shell), we need:
- A.
Principal and Azimuthal quantum number
- B.
Principal and magnetic Quantum number
- C.
Azimuthal and Magnetic Quantum number
- D.
Principal, Azimuthal and Magnetic quantum number
- 17.Which of the following statement is not true about the quantum numbers n, l, ml, ms
- A.
Ml gives information on the energy of the electron in a given orbital
- B.
L gives an idea about the shape of an orbital
- C.
N gives information on the size of the orbital
- D.
S gives the direction of spin of the electron in the orbital
- 18.The Balmer series of spectral lines arise when an electron in an excited Hydrogen atom jumps from an energy level
- A.
N = 5 to n = 1
- B.
N = 5 to n = 3
- C.
N = 5 to n = 4
- D.
N = 5 to n = 2
- 19.Which of the following set of quantum numbers is not valid?
- A.
N = 1, l = 2
- B.
N = 2, m = 1
- C.
N = 3, l = 0
- D.
N = 4, l = 2
- 20.Which of the following is not the characteristic of Planck's Quantum theory of radiation?
- A.
The energy is not absorbed or emitted in whole number or multiples of quantum
- B.
Radiation is associated with energy.
- C.
Radiation is not emitted or absorbed.continuously but in the form of small packets called quanta.
- D.
Magnitude of energy associated with quantum is proportional to the frequency.
- 21.
An isotone of 32Ge76 is:
- A.
Only (i) and (ii)
- B.
Only (ii) and (iii)
- C.
Only (ii) and (iv)
- D.
(ii), (iii) and (iv)
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