CBSE Class 9 Answered

Principal quantum number (n):

Has positive values of 1, 2, 3, etc.

 As n increases, the orbital becomes larger and this means that the electron has a higher energy level and is less tightly bound to the nucleus.

Azimuthal quantum number (l ):

Has values from 0 to n – 1.

 This defines the shape of the orbital, and the value of l is designated by the letters s, p, d, and f, which correspond to values for l of 0, 1, 2, and 3.

In other words, if the value of l is 0, it is expressed as s; if l = 1 = p, l = 2 = d, and l = 3 = f.

Magnetic quantum number (m_l):

Determines the orientation of the orbital in space relative to the other orbitals in the atom.

This quantum number has values from -l through 0 to +l.

Spin quantum number (m_s):

Specifies the value for the spin and is either +1/2 or -1/2.

No more than two electrons can occupy any one orbital.

In order for two electrons to occupy the same orbital, they must have opposite spins