Explain any one of the following statements:
i) The transition metals are well known for the formation of interstitial compounds.
ii) The largest number of oxidation states is exhibited by manganese in the first series of transition elements.
i) The transition metals are well known for the formation of interstitial compounds.
ii) The largest number of oxidation states is exhibited by manganese in the first series of transition elements.
Solution
(i) Transition-metal crystals contain octahedral/tetrahedral interstices of just the right size for small atoms such as H, C and N. These become trapped inside the lattice, forming interstitial compounds (TiC, MnN, steels) that are typically non-stoichiometric, very hard and high-melting.
(ii) Manganese, [Ar]3d4s, has the maximum number of electrons available for bond formation or removal — two 4s and five unpaired 3d — so it exhibits every oxidation state from +2 to +7 (MnO to MnO), the widest range in the 3d series.
(ii) Manganese, [Ar]3d4s, has the maximum number of electrons available for bond formation or removal — two 4s and five unpaired 3d — so it exhibits every oxidation state from +2 to +7 (MnO to MnO), the widest range in the 3d series.
CBSE Class 12 Board · 2007 · Foreign · Subjective