Explain $d$-block elements of the periodic table.

(N/A) Elements of group $3$ to $12$ are known as $d$-block elements.
The general electronic configuration of these elements is $(n-1)d^{1-10}ns^{0-2}$.
These elements are called $d$-block elements because their last electron enters the $d$-orbital.
Characteristics of $d$-block elements:
- They are all metals. They mostly form coloured ions,exhibit variable valency (oxidation states),show paramagnetism,and are often used as catalysts.
- However,$Zn$,$Cd$,and $Hg$,which have the electronic configuration $(n-1)d^{10}ns^{2}$,do not show most of the properties of transition elements.
Transition Elements: Transition metals form a bridge between the chemically active metals of $s$-block elements and the less active elements of groups $13$ and $14$,hence the name "Transition Elements".