CBSE Class 12 · 2023 · d and f Block ElementsLong Answer

(a) A transition element X has the electronic configuration [Ar]4s²3d³. Predict its likely oxidation states.

Answer: X is vanadium (Z = 23); likely states: +2, +3, +4 and +5 (+5 the highest, using all 3d and 4s electrons).

Solution

[Ar]4s

^{2}

^{3}

→ Z = 23, the element is vanadium.
Its five valence electrons (two 4s + three 3d) can participate progressively, giving the oxidation states

+ 2, + 3, + 4, + 5

^{2 +}

, V

^{3 +}

, VO

^{2 +}

(+4), VO

_{2}^{+}

_{2}

_{5}

(+5) — the +5 state uses all five electrons).

CBSE Class 12 Board · 2023 · Subjective