Consider the given two statements:

Assertion (A):	All d orbitals are tetra-lobed structures having two nodal planes.
Reason (R):	Out of five, only four d-orbitals are degenerate orbitals.

 

1.	Both (A) and (R) are True and (R) is the correct explanation of (A).
2.	Both (A) and (R) are True but (R) is not the correct explanation of (A).
3.	(A) is True but (R) is False.
4.	Both (A) and (R) are False.

The number of protons, neutrons and electrons in  \( _{71}^{175}Lu\) respectively, are:

1. 104, 71 and 71

2. 71, 71 and 104

3. 175, 104 and 71

4. 71, 104 and 71

The energy of an electron in the first Bohr's orbit of an H-atom is -13.6 eV. The possible energy value (s) of the excited state(s) for electrons in Bohr's orbits of hydrogen is (are):

1. -3.4 eV

2. -4.2 eV

3. -6.8 eV

4. +6.8 eV

Which of the following ions has the same radius as the first Bohr orbit of the hydrogen atom?

1. ${\mathrm{He}}^{+},$ $n=2$

2. ${\mathrm{Li}}^{2+},n=2$

3. ${\mathrm{Be}}^{3+},$ $n=2$

4. ${\mathrm{Li}}^{2+},\mathrm{n}=3$

The number of electrons with the azimuthal quantum number l = 1 and 2 for Cr ₂₄ in ground state is

1. 16 and 5

2. 12 and 5

3. 16 and 4

4. 12 and 4

The wavelength of the radiation emitted when in a H atom, the electron falls from infinity to stationary state (n=1), is:

1. $15$ $nm$

2. 192 nm

3. 406 nm

4. 91 nm

The number of unpaired electrons in 1s² 2s² 2p³ is -

1. 2

2. 0

3. 3

4. 1

The concept that contradicts the Bohr Model of an atom is: 

Electrons are emitted with zero velocity from a metal surface when it is exposed to radiation of wavelength 6800 Å. The work function (W₀) of the metal is: 

1. 3.109 × 10^–20 J

2. 2.922 × 10^–19 J

3. 4.031 × 10¹⁹ J

4. 2.319 × 10^–18 J

Determine the maximum number of emission lines produced when an electron in a hydrogen atom transitions from the n = 6  energy level to the ground state :

1. 30

2. 21

3. 15

4. 28