Question

Name
(a) three elements that have a single electron in their outermost shells.

Answer 1

Lithium $\left(Li\right)$, sodium $\left(Na\right)$ and potassium $\left(K\right)$ have a single electron in their outermost shells.

Element	Electronic configuration	Valence electrons	Group
$Li\left(3\right)$	$2,1$	$1$	$1$
$Na\left(11\right)$	$2,8,1$	$1$	$1$
$K\left(19\right)$	$2,8,8,1$	$1$	$1$