Identify and name the metals from the following elements whose electronic configurations are given below:
$(a)$ $2, 8, 2$
$(b)$ $2, 8, 1$
$(c)$ $2, 8, 7$
$(d)$ $2, 1$

(A, B, D) Metals are elements that typically have $1, 2,$ or $3$ electrons in their outermost shell.
$(a)$ Electronic configuration $2, 8, 2$: The valence shell has $2$ electrons. This is Magnesium $(Mg)$.
$(b)$ Electronic configuration $2, 8, 1$: The valence shell has $1$ electron. This is Sodium $(Na)$.
$(c)$ Electronic configuration $2, 8, 7$: The valence shell has $7$ electrons. This is a non-metal (Chlorine,$Cl$).
$(d)$ Electronic configuration $2, 1$: The valence shell has $1$ electron. This is Lithium $(Li)$.
Therefore,the metals are $(a)$,$(b)$,and $(d)$.