In context of the lanthanoids, which of the following statement is not correct ?
(a) There is a gradual decrease in the radii of the members with increasing atomic number in the series.
(b) All the members exhibit +3 oxidation state.
(c) Because of similar properties the separation of lanthanoids is not easy.
(d) Availability of 4f electrons results in the formation of compounds in +4 state for all the members of the series.
Correct option (d) Availability of 4f electrons results in the formation of compounds in +4 state for all the members of the series.
Explanation:
(a) There is a gradual decrease in the radii of the lanthanoids with increasing atomic number - a case of lanthanide contraction, thus true.
(b) lonisation potential for the formation of Lu3+ is comparatively low, hence +3 state is favorable, thus true.
(c) Due to lanthanoid contraction-Zr and Hf; Nb and Ta, Mo and W have the same size and thus similar properties and thus separation is not easy, thus true.
(d) Formation of +4 state requires very high energy, thus incorrect.