The electronic configuration of an element $X$ is $2, 8, 2$.
$(a)$ Find the number of electrons present in the atom of element $X$.
$(b)$ Write the atomic number.
$(c)$ Is this element $X$ a metal or a non-metal?
$(d)$ Find out the valency of the element $X$.

(A) The total number of electrons is the sum of electrons in each shell: $2 + 8 + 2 = 12$ electrons.
$(b)$ The atomic number of a neutral atom is equal to the total number of electrons. Therefore,the atomic number is $12$.
$(c)$ Since the element has $2$ electrons in its outermost shell,it tends to lose these electrons to achieve a stable octet configuration. Elements that lose electrons to form positive ions are classified as metals. Thus,$X$ is a metal.
$(d)$ The valency is determined by the number of electrons in the outermost shell. Since $X$ has $2$ valence electrons,it loses $2$ electrons to complete its octet. Therefore,the valency of $X$ is $+2$.