Identify and name the metals out of the following elements whose electronic configurations are given below.
a) 2,8,2 `" "` b] 2,8,`" "` c] 2, 8, 7 `" "` d] 2,1 

Explanation

Elements with 1 to 3 valence electrons are usually metals whereas elements with 4 or more valence electrons are usually non-metals or metalloids.
From given electronic \configurations, elements (a), (b), and (d), which have 2, 1, and I valence electrons respectively are metals. They are identified as:
(a) 2, 8, 2 - Magnesium (12)
(b) 2, 8, 1 - Sodium (11)
(c) 2, 1 - Lithium (3)