Question

U
write the Valence shell
electronic configuration of the
atom of the following elements. (a) An element present in periods 3 of group VA

(b) An element present in period 2
of group VIA.
​

Answer 1

Explanation:

a)the third period contains eight elements : sodium, magenisum , aluminium, silicon, phosphorus, sulfur, chlorine, and argon.

b) the second period contains the element lithium, beryllium, boron, carbon, nitrogen, oxygen, fluorine, and neon. In a quantum mechanical descripition of atomic structure , this period corresponds to the filling of the seonds ( n=2) shell, more specially its 2s and 2p subshells.

Answer 2

Explanation:

third period 4th group element is phosphorus the valency of phosphorus is 3 s2p3 and 2nd period 6th element is oxygen valency of oxygen is 6