Chemistry · Structure of Atom

JEE Main 2026 — 23 January, Morning Shift — Question 58

Given:

(A) $n=5,\ m_\ell=-1$

(B) $n=3,\ \ell=2,\ m_\ell=-1,\ m_s=+\frac{1}{2}$

The maximum number of electrons in an atom that can have the above quantum numbers respectively are:

Answer: D

(A)

For $n=5$ and $m_\ell=-1$ , the value $\ell$ must allow $m_\ell=-1$ .

Possible $\ell$ values are $\ell=1,2,3,4$ .

Each allowed subshell has one orbital with $m_\ell=-1$ .

Each orbital can hold 2 electrons.

Total electrons $= 4 \times 2 = 8$

(B)

All four quantum numbers are fixed, thus we have

$n=3,\ \ell=2,\ m_\ell=-1,\ m_s=+\frac{1}{2}$

This specifies a unique electron.

Maximum number of electrons = 1

Thus, the correct answer is option D.

Answer key and solution verified before publishing.

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