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Answer the following.
Explain why: Mn²⁺ is more stable than Fe²⁺ towards oxidation to +3 state. (At. no. of Mn = 25, Fe =…
Explain why:
(i)[1]
$\text{Mn}^{2+}$ is more stable than $\text{Fe}^{2+}$ towards oxidation to $+3$ state. (At. no. of $\text{Mn} = 25$, $\text{Fe} = 26$)
(ii)[1]
Transition elements usually form coloured ions.
(iii)[1]
Zr and Hf exhibit similar properties. (At. no. of $\text{Zr} = 40$, $\text{Hf} = 72$)
Answer
Answer (i)
Because $\mathrm{Mn^{2+}}$ has the stable half-filled configuration $3d^5$, whereas $\mathrm{Fe^{2+}}$ ($3d^6$) on oxidation to $\mathrm{Fe^{3+}}$ ($3d^5$) attains the half-filled stable configuration, so $\mathrm{Fe^{2+}}$ is easily oxidised.
Answer (ii)
Because they have partly filled d-orbitals, so they undergo d-d transitions: electrons absorb light of a certain wavelength from the visible region and the complementary colour is seen.
Answer (iii)
Because of the lanthanoid contraction, the atomic (ionic) radii of Zr and Hf are almost equal, so they have similar properties.