Question

Statements that are true of transition and inner transition metals are :

• A. osmium is the heaviest transition metal
• B. $C{u}^{+}\left(3d^{10}\right)$ is more stable than $C{u}^{2+}\left(3d^9\right)$ in aqueous medium
• C. actinides are generally strong reducing agents
• D. $Y,La$ and $Ac$ exhibit variable valency

Answer 1

Answer: (A), (C)

The correct options are
A osmium is the heaviest transition metal
C actinides are generally strong reducing agents

Osmium is the densest and heaviest metal.

$C{u}^{2+}$ has smaller size and greater charge and hence is more extensively hydrated than $C{u}^{+}.$ Hence though $C{u}^{+}\left(3d^{10}\right)$ has completed 'd' level, $C{u}^{2+}$ is more stable than $C{u}^{+}$ in aqueous solution.

Actinides are highly electropositive (means higher oxidation potential) and hence are good reducing agents.

Y, Ac and La have $(n-1)d^{1}n{s}^2$ configuration. So, all three exhibit only +3 oxidation state.