Which of the following molecule is not paramagnetic:
1. $C{u}^{++}$

2. $F{e}^{2+}$

3. $C{l}^{-}$

4. None of the above 

The radius of a hydrogen shell is 0.53Å. In its first excited state, radius of the shell will be:
1. 2.12 Å
2. 1.06 Å
3. 8.5 Å
4. 4.24 Å

Uncertainty in position of a $e^{-}$ and He is similar. If uncertainty in momentum of $e^{-}$ is $\mathrm{32 }\times {10}^5$, then uncertainty in momentum of He will be:

The ionization energy required to remove an electron from the second orbit of \(\text{Li}^{2+}\) is:
1.  122.4 eV
2.  40.8 eV
3.  30.6 eV
4.  13.6 eV

If the energy value is E = 3.03 × 10^–19 Joules, (h = 6.6×10^–34 J x sec., C = 3×10⁸ m/sec), then the value of the corresponding wavelength is:

The number of orbitals indicated by the following set of quantum numbers, n = 3, l = 2, m =+2 is:

1.  1

2.  2

3.  3

4.  4

In the Hydrogen atom, the energy of the first excited state is – 3.4 eV. Then find out K.E(kinetic energy) of the same orbit of the Hydrogen atom:

1. + 3.4 eV

2. + 6.8 eV

3. – 13.6 eV

4. + 13.6 eV

The value of Planck's constant is 6.63 × 10^–34 J s. The velocity of light is 3.0 × 10⁸ m s^–1. The closest value to the wavelength in nanometers of a quantum of light with a frequency of $8\times {10}^{15}$ ${\mathrm{s}}^{-1}$ is:

1. $2\times {10}^{-25}$

2. $5\times {10}^{-18}$

3. $4\times {10}^1$

4. $3\times {10}^7$

The frequency of radiation emitted when the electron falls from n = 4 to n = 1 in a hydrogen atom will be:
(Given ionization energy of H = 2.18 × 10^–18 J atom ^–1 and h = 6.625 × 10^–34 Js):

1. 1.03 × 10¹⁵ s^–1

2. 3.08 × 10¹⁵ s^–1

3. 2.00 × 10¹⁵ s^–1

4. 1.54 × 10¹⁵ s^–1

The nuclei of which one of the following pairs are isotones: