CBSE Class 12 · 2023 · d and f Block ElementsMultiple Choice

Which of the following ions has the electronic configuration 3d

^{6}

? (Atomic numbers: Mn = 25, Co = 27, Ni = 28)

Answer: (B)

Solution

Co (Z = 27): [Ar]3d

^{7}

^{2}

; removing three electrons (two 4s, one 3d) gives

C o^{3 +} : [Ar] 3 d^{6}

Checking the others: Ni

^{3 +}

= 3d

^{7}

, Mn

^{2 +}

= 3d

^{5}

, Mn

^{3 +}

= 3d

^{4}

.
Correct option: (B).

CBSE Class 12 Board · 2023 · Single correct option