Question

Which one of the following elements exhibits a maximum number of valence electrons?

• A. Na
• B. Al
• C. Si
• D. P

Answer 1

The correct option is D

P

Explanation for correct option

(D) P

Valence electrons

• The electrons that are added to the electronic shell with the highest principal quantum number are called valence electrons.

P (Phosphorus)

• The number of electrons of Phosphorus $\left(\mathrm{P}\right)$ is $15$.
• The electronic configuration is as follows:

$\mathrm{P}=1{\mathrm{s}}^2,2{\mathrm{s}}^2,2{\mathrm{p}}^6,3{\mathrm{s}}^2,3{\mathrm{p}}^3$

• The number of valence electrons of Phosphorus is $5$.

Explanation for incorrect options

(A) Na (Sodium)

• The number of electrons of Sodium is $11$.
• The electronic configuration is as follows:

$\mathrm{Na}=1{\mathrm{s}}^2,2{\mathrm{s}}^2,2{\mathrm{p}}^6,3{\mathrm{s}}^1$

• The number of valence electrons of sodium is $1$.

(B) Al (Aluminum)

• The number of electrons of Aluminum is $13$.
• The electronic configuration is as follows:

$\mathrm{Al}=1{\mathrm{s}}^2,2{\mathrm{s}}^2,2{\mathrm{p}}^6,3{\mathrm{s}}^2,3{\mathrm{p}}^1$

• The number of valence electrons of Aluminum is $3$.

(C) Si (Silicone)

• The number of electrons of Silicone is $14$.
• The electronic configuration is as follows:

$\mathrm{Si}=1{\mathrm{s}}^2,2{\mathrm{s}}^2,2{\mathrm{p}}^6,3{\mathrm{s}}^2,3{\mathrm{p}}^2$

• The number of valence electrons of Silicone is $4$.

Phosphorus has a maximum number of valence electrons that is $5$. Therefore, the correct option is (D) P.