Question

Which one of the following orbitals can hold only two electrons?

• A. $3s$
• B. $2p$
• C. $4d$
• D. $5f$

Answer 1

The correct option is A

$3s$

Explanation for correct option

(A) $\mathbf{3}\mathit{s}$

Electronic configuration

• The electronic configuration of an element is the arrangement of electrons in the atomic orbitals.
• They use the standard notation to arrange atomic sub-shells in ascending order of energy.
• There are four different kinds of orbitals, denoted $s,p,d$ and $f$.
• The maximum number of electrons in $s$ orbital is $2$.
• The maximum number of electrons in $p$ orbital is $6$.
• The maximum number of electrons in $d$ orbital is $10$.
• The maximum electrons in $f$ orbital is $14$.

$\mathbf{3}\mathit{s}$ orbital

• The $s$ orbital can hold $2$ electrons.
• Therefore, $3s$ orbital can have only $2$ electrons.

Explanation for incorrect options

(B) $\mathbf{2}\mathit{p}$

• $2p$ orbital can hold up to $6$ electrons.

(C) $\mathbf{4}\mathit{d}$

• $4d$ orbital can hold up to $10$ electrons.

(D) $\mathbf{5}\mathit{f}$

• $5f$ orbital can hold up to $14$ electrons.

Therefore, the correct option is (A) $\mathbf{3}\mathit{s}$.