Question

The elements in the third period, namely, Na, Mg, Al, Si, P, S, Cl and Ar have electrons in the three shells, K, L, M. Write down the electronic configuration of these elements.

Answer 1

Elements	K Shell	L Shell	M Shell	Electronic configuration
Na	2	8	1	2, 8, 1
Mg	2	8	2	2, 8, 2
Al	2	8	3	2, 8, 3
Si	2	8	4	2, 8, 4
P	2	8	5	2, 8, 5
S	2	8	6	2, 8, 6
Cl	2	8	7	2, 8, 7
Ar	2	8	8	2, 8, 8