Question

In a given atom no two electrons can have the same values of all the four quantum numbers. This is called

• A. Hund's rule
• B. Aufbau principle
• C. Uncertainty principle
• D. Pauli- exclusion principle

Answer 1

Answer: (D)

Pauli- exclusion principle

Answer 2

According, to Pauli's exclusion principle -no two electrons in an atom can have the same values of all the four quantum numbers. In $1s^2$ for I electron n = 1, l = 0,xn = 0,s = $\frac{1}{2}$ for II electron n = l,l = 0,m = 0,s =$-\frac{1}{2}$ It means if the values of n, l, and m are same, then the value of spin quantum number must be different, i.e. +1/2 and -1/2.