Question

Whih of the followin statement are correct?
A. Transition elements higher enthalpies of atomization as they have stronger interatomic interaction
B. `IE_(2)` of `._23Vlt._24Crgt._25Mn` and `._28 Nilt._29Cugt._30Zn`
C. `Ni(II)` compounds are more stable than pt(II) where as Pt(IV) compounds are stable than nickel(IV).
D. The element which gives the greatest number of oxidation state does not occur in or near the middle of the series.

Answer 1

Correct Answer - ABC
(A) Greater the number of valence electrons, stronger is the resultant bonding and thus greater is the enthalpies of atomization.
(B) `Cr^(+)` has half-filled valence shell electron configuration `3d^(5)`, so it has higher second ionisation energy. Similarly `Cu^(+)` has completely filled stable valence shell electron configuration `3d^(10)`, So it has higher second ionisation energy.
(C) Sum of first two ionisation energies `(IE_(1)+IE_(2))` of `Ni(II)` is less than that of `Pt(II)`. Similarly sum of first four ionisation energies of `Pt(IV)` is less than that of `Ni(IV)`.
(D) Element occurs in the middle of the period, e.g., manganese has `+7` oxidation state as it contain five unpaired electrons.