Question

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

• A. $36$
• B. $49$
• C. $33$
• D. $34$

Answer 1

The correct option is C $33$

Atomic number of the given element is $15$ and it belongs to group $15$.
The electronic configuration of the element which is just below this element in the periodic table will be
$1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{10}4p^3$
Therefore atomic number of the element below the above element $=15+18=33.$