Mention the direct consequence of the following factors on the chemical behaviour of the transition elements:
i) They have incompletely filled d-orbitals in the ground state or in one of their oxidised states.
ii) They contribute more valence electrons per atom in the formation of metallic bonds.
i) They have incompletely filled d-orbitals in the ground state or in one of their oxidised states.
ii) They contribute more valence electrons per atom in the formation of metallic bonds.
Solution
(i) Incompletely filled d-orbitals give the transition elements their characteristic chemistry: variable oxidation states, coloured ions (d–d transitions), paramagnetism (unpaired d electrons), a strong tendency to form complexes, and catalytic activity.
(ii) With both ns and (n−1)d electrons available for the metallic bond, the bonding is very strong — hence their high melting and boiling points, large enthalpies of atomisation, high densities and hardness.
(ii) With both ns and (n−1)d electrons available for the metallic bond, the bonding is very strong — hence their high melting and boiling points, large enthalpies of atomisation, high densities and hardness.
CBSE Class 12 Board · 2002 · Delhi · Subjective