MolSynapsequestion bank

MolSynapse / Question bank / Atomic Structure / Quantum numbers, orbitals, nodes, electronic configuration

NEET levelSingle correct optionDifficulty 1 of 3as194

The ground-state electronic configuration of chromium ( $Z = 24$ ) is

A $[Ar] 3 d^{4} 4 s^{2}$
B $[Ar] 3 d^{5} 4 s^{1}$
C $[Ar] 3 d^{6}$
D $[Ar] 3 d^{3} 4 s^{2} 4 p^{1}$

Answer: B

Half-filled

3 d^{5}

together with a singly filled

4 s

has extra exchange energy and lower repulsion, so Cr is

[Ar] 3 d^{5} 4 s^{1}

rather than

3 d^{4} 4 s^{2}

.

Practice Atomic Structure More on Quantum numbers, orbitals, nodes, electronic configuration

Previous questionNext question

More questions on Quantum numbers, orbitals, nodes, electronic configuration