Aluminium, being able to form $+3$ ions easily, is more electropositive than thallium.

Given below are two statements: one is labelled as Assertion $\mathrm{A}$ and the other is labelled as Reason $\mathrm{R}$.

Assertion $\mathrm{A}:$ In $\mathrm{T}l{\mathrm{I}}_3,$ isomorphous to ${\mathrm{CsI}}_3$, the metal is present in $+1$ oxidation state.

Reason $\mathrm{R}:$ $\mathrm{T}l$ metal has fourteen $\mathrm{f}$ electrons in its electronic configuration.

In the light of the above statements, choose the most appropriate answer from the options given below:

Given below are two statements:

Statement I: Boron is extremely hard indicating its high lattice energy.

Statement II: Boron has highest melting and boiling point compared to its other group members.

In the light of the above statements, choose the most appropriate answer from the options given below

Why thallium have positive standard reduction potential while other elements in group 13 have negative reduction potential?$\left(\mathrm{M}+3{\mathrm{e}}^{-}\to {\mathrm{M}}^{3+}\right)$

Give reason why: Aluminium wire is used to make transmission cables.