Question

Give reason for the following:

Hydrogen forms a positive ion just like metals. Still, it combines with very reactive metals

Answer 1

Hydrogen forms a positive ion just like metals. still, it combines with very reactive metals

• The reason is that Hydrogen has one electron on its outermost shell similar to alkali metal. Alkali metals have one electron as it gives that electron to another atom. the valency of alkali metal is +1. so like alkali metals hydrogen gives one electron and becomes an H⁺ ion, which shows +1 valency.
• In Halogen, they have 7 electrons on the outermost shell and they need one electron to complete its octet so their valency is -1. so like halogen, hydrogen needs one electron to complete its outermost shell. so both of them gain electrons and hydrogen become H^- ions, which shows -1 valency.
• On reacting with non-metal, hydrogen becomes an H⁺ ion. for eg: HCl
• On reacting with metal, hydrogen becomes H^- ions. for eg: NaH
• And so the position of the hydrogen is non-certain in periodic table.