Explain the following observations giving an appropriate reason for each.
(i) The enthalpies of atomization of transmition elements are quite high.
(ii) There occurs much more frequent matal-matal bonding in compounds of heavy transition metals (i.e, `3^(rd)` series).
(iii) `Mn^(2+)` is much more resistant then `Fe^(2+)` toawards oxidation.

Explanation

(i) The enthalpy of atomisation of transmition elements are quite high, because the metallic bond present between theim atoms are strong. The is due to strong metallic bonding.
(iii) There occurs much more frequent metal-metal bonding in compounds of heavy transition metal . Creater the number of unpaired electrons stronger and more frequent is the resultant bonding.
(iii) `Mn^(2+)` has stable half filled `(3d^(5))` configuration .Hence does not get oxidised . But `Fe^(2+)` has `3d^(6)` configuration , if can lose 1 electrons to become the more stable `Fe^(3+)` of `3d^(5)` configuration or `Fe^(2+)` easily gets oxidised.