Which set of quantum numbers among the following is invalid?

1.	n = 1 and $\mathcal{l}$= 2	2.	n=2 and m = 1
3.	n =3 and $\mathcal{l}$= 0	4.	n = 4 and $\mathcal{l}$= 2

When the atoms of gold sheet are bombarded with a beam of $\alpha$ -particles, only a few alpha-particles get deflected where as most of them go straight undeflected. This is because:

How many unpaired electrons are present in the electronic configuration 1s² 2s² 2p³?

1. Two (2)

2. Zero (0)

3. Three (3)

4. One (1)

Two radiations have wavelengths  \(8000\) Å and  \(16000\) Å, with corresponding energies \(E_1\)​ and \(E_2\)​, respectively. Establish the relationship between \(E_1\)​ and \(E_2\)​.

1. \(E_1=6E_2\)
2. \(E_1=2E_2\)
3. \(E_1=4E_2\)
4. \(E_1=1 / 2 E_2\)

An atom has a mass number of 13 and contains 7 neutrons. Determine its atomic number:

1. 6

2. 7

3. 4

4. 5

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

1. –3.4 eV 

2. –4.2 eV

3. –6.8 eV 

4. +6.8 eV

Two electrons occupying the same orbital are distinguished by:

1. Magnetic quantum number
2. Azimuthal quantum number
3. Spin quantum number
4. Principal quantum number

Maximum number of electrons in a subshell with l = 3 and n = 4 is:

1. 14

2. 16

3. 10

4. 12

Consider the following sets of quantum numbers:

Which of the following sets of quantum numbers is not possible?

1. ii, iii, and iv
2. i, ii, iii, and iv
3. ii, iv and v
4. i and iii

The maximum number of electrons that can be accommodated in the subshell with azimuthal quantum number l = 4, is:

1. 10

2. 8

3. 16

4. 18