Explain the following - (a) Melting point of Fe is higher than that of Cu. (b) Magnetic moment of `Ni^(2+)` is lower than that of `Co^(2+)`. (c ) Scandium does not produce coloured ions but still it is a transition element. (d) The increasing order of oxidation states of the oxo - ions is : `VO_(2)^(+)lt CrO_(7)^(2-)lt MnO_(4)^(-)`

Explanation

(a) N/A (b) N/A (c ) Sc ghas partially filled d - orbitals in its penultimate shell but `Sc^(3+)` has no d - electron and thus d - d transition is not possible (d) N/A