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Identify which of the following statements are INCORRECT: (i) % covalent character order: LiCl < NaCl < KCl < RbCl (ii) The maximum covalency achievable by any halogen (including F) is 7. (iii) First ionisation potential of M2+ is greater than first electron affinity of M3+. (iv) Electron affinity order: S > Se > Te > O (v) Electronegativity order: Li < Be < B < C (vi) Ionic size order: Mg2+ < Na < F- (vii) Hydrated ionic size order: Li+ > Na+ > K+ (viii) Lattice energy order: NaCl > MgCl2 > AlCl3

1. (i), (ii), (iii), (iv)
2. (ii), (iii), (vi), (viii)
3. (iii), (v), (vi), (vii)
4. (i), (iv), (v), (vii)

Correct answer: (ii), (iii), (vi), (viii)

Solution

(i) By Fajan's rules, smaller cation polarises more → more covalent. LiCl is the MOST covalent, so the correct order of covalent character is RbCl < KCl < NaCl < LiCl. Statement (i) has it reversed — it IS incorrect. (ii) F has no d-orbitals; its maximum covalency is 1, not 7. (ii) is incorrect. (iii) IP1(M2+) = removing e- from M2+; EA1(M3+) = adding e- to M3+. These are the exact reverse process; magnitudes are equal. Saying IP1 > EA1 is incorrect. (iv) S > Se > Te > O for electron affinity is actually correct (O has anomalously low EA due to small size/electron repulsion). (iv) is correct, not incorrect. (v) Electronegativity: Li(1.0)<Be(1.5)<B(2.0)<C(2.5) — correct trend. (v) is correct. (vi) Comparing Mg2+(ionic) with Na(atomic) with F-(ionic) mixes different quantities; additionally size: Mg2+ < F- < Na (atomic). The stated order Mg2+ < Na < F- puts Na between them which is wrong if we compare all as species with radius. (vi) is incorrect. (vii) Smaller ion → stronger hydration shell → larger hydrated radius: Li+ > Na+ > K+. (vii) is correct. (viii) Lattice energy increases with charge: AlCl3 > MgCl2 > NaCl. Statement says NaCl > MgCl2 > AlCl3 which is wrong. (viii) is incorrect. Incorrect statements: (ii),(iii),(vi),(viii).

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