Question

An element X having atomic no. 17 and Y having atomic no. 18. Name the elements. Write its electronic configuration, valency and state which is more reactive elements and why?

Answer 1

Chlorine has 17 atomic no

Argon has 18 atomic no

Answer 2

X symbolises Chlorine which is an electronegative element from the family of halogens.

The electronic configuration is (2,8,7).

The valency is 1.

Y symbolises Argon which is an inert gas element of 18 th group .

The electronic configuration is(2,8,8).

The valency is 0 because it has a stable structure with M shell filled.

Chlorine is more reactive than argon because argon is stable it doesn't take part in chemical reactions. Hence chlorine is the most electronegative element of period 3.

As it takes part in reaction and it's a greenish poisonous gas .

Hope it help.