Question

why hydrogen doesn't belong to any group

Answer 1

Hydrogen is placed above Group 1 in Alkali metals, but it doesn’t really belong to any group.

This is because it shows properties similar to both Alkali Metals as well as Halogens.

Answer 2

Properties of Hydrogen. Hydrogen is a nonmetal and is placed abovegroup in the periodic table because it has ns1 electron configuration like the alkali metals. However, it varies greatly from the alkali metals as it forms cations (H+) more reluctantly than the other alkali metals.