Chemistry - f-block Question with Solution | TestHub

Question Explanation:

Find the correct statement(s).

Concept:

This question is based on properties of f-block elements.

Solution:

(I) ${\mathrm{La}}^{3+}$ and ${\mathrm{Lu}}^{3+}$ do not show any colour because, ${\mathrm{La}}^{3+}$ has noble gas configuration of [Xe], and ${\mathrm{Lu}}^{3+}$ has completely filled 4 f subshell, means no unpaired electron to cause colour.

(II) ${\mathrm{Sm}}^{3+},{\mathrm{Lu}}^{3+}$ are coloured species but ${\mathrm{La}}^{3+}$ is not.

(III) Ce is known to form a stable +4 oxidation state (noble gas configuration)

(IV) Gd and Eu are known to form stable +2 and +3 oxidation state respectively.

(V) Uranium and plutonium are known for +6 and +4 oxidation states respectively.

(VI) Gadolinium has 7 unpaired electrons in the ground state.