Metallic character is highest for the element with configuration

Elements with ${\mathrm{ns}}^1$  configuration have maximum metallic character
Down the group metallic character  $\uparrow$

$\begin{array}{l}\therefore \mathrm{Li}<\mathrm{Na}<\mathrm{K}<\text{}\mathrm{Rb}<\mathrm{Cs}\\ 2{\mathrm{s}}^{1}3{\mathrm{s}}^{1}4{\mathrm{s}}^1 5{\mathrm{s}}^{1 }6{\mathrm{s}}^1\end{array}$