Question

(i) Why group 17 elements are highly reactive?
(ii) How many electrons do inert gases have in their valence shells?

Answer 1

1. Group 17 elements require just one electron to complete their octet. They easily react with other elements to achieve the nearest stable gas configuration. Thus, they are highly reactive.
2. Noble gases have fully filled valence shells. Therefore, helium has 2 electrons in its valence shell. All other noble gases have 8 electrons in their valence shells.