Question

The electronic configuration of an element is $1s^{2}2s^{2}2p^{6}3s^{2}3p^3$. The atomic number of the element which is just below the above element in the periodic table is :

• A. $49$
• B. $31$
• C. $34$
• D. $33$

Answer 1

The correct option is D $33$

Atomic number of the given element = 2+2+6+2+3 = 15

This is phosphorus. The atomic number of element below phosphorus will be calculated by adding 18 into the atomic number phosphorus, i.e., 15+18 = 33.