Question

The number of valence electrons in an atom with electronic configuration $1s^{2}2s^{2}2p^{6}3s^{2}3p^3$ is:

• A. 2
• B. 3
• C. 5
• D. 11

Answer 1

The correct option is C 5

Valence electrons are the electrons present in the outermost shell of an atom.

Here in the given configuration $1s^{2}2s^{2}2p^{6}3s^{2}3p^3$, the 3rd shell is the outermost shell and it contains $5$ electrons which are presnt in $3s^{2}3p^3$.

Hence option $C$ is correct.