Question

06- An element X having mass number 35 and number of neutron present is 18. Identify the element X.
Write its electronic configuration and also valency.​

Answer 1

no. of proton=35-18=17

no.of proton is the atomic no. of the element

so the given element is chlorine

electronic configuration of chlorine= 2,8,7

valency of chlorine= 1

Answer 2

Mass number of the element=35

no of neutrons=18

Mass number= no of neutrons+number of proton.

35=x+18

x=35-18

x=17

The no of protons and electrons present in element X is 17 (no of proton= no of electron)

Hence, the element is Chlorine

electronic configuration

1s2 2s2 2p6 3s2 3p5

Valency= 1