Question

Mark the correct statement(s).
(i) Manganese exhibits $+7$ oxidation state
(ii) Zinc forms coloured ions
(iii) $\left[ CoF _6\right]^{3-}$ is diamagnetic
(iv) $Sc$ forms $+4$ oxidation state
(v) $Zn$ exhibits only $+2$ oxidation state

• A. (i) and (ii)
• B. (i) and (v)
• C. (ii) and (iv)
• D. (iii) and (iv)

Answer 1

Answer: (B)

(i) Outer electronic configuration of $Mn$ is $3 d^5 4 s^2$ and hence exhibits $+7$ oxidation state.
(ii) Zinc does not form coloured ions as it has completely filled $3 d^{10} 4 s^2$ configuration.
(iii) In $\left[ CoF _6\right]^{3-}, Co ^{3+}$ is a $d^7$ system. Fluoride is a weak field ligand and hence, does not cause pairing of electrons.

(iv) Sc can form a maximum of $+3$ oxidation state as it has an outer electronic configuration of $3 d^1 4 s^2$.
(v) $Zn$ exhibits only $+2$ oxidation state as this $O.S$. is the most stable one.