NTSE Stage 2 SAT 2016 Question Paper

The electronic configuration of
$\mathrm{X}\to 2,8,1\Rightarrow \mathrm{Na}$
And the electronic configuration of
$\mathrm{Y}\to 2,8,7\Rightarrow \mathrm{Cl}$
Compound $\left(\mathrm{Z}\right)\Rightarrow \mathrm{NaCl}\Rightarrow$ It is good conductor of electricity in molten and fused state but not in solid state.