Question

Why is hydrogen placed in the first group if it is not an alkali metal?

Answer 1

Hydrogen is a special element because it accepts as well as rejects electrons to attain stable configuration.As the elements progress from left to right, the number of electrons and protons increase by one. Hydrogen has 1 electron and 1 proton so it is the first element listed.

Answer 2

Hydrogen is a nonmetal and is placed above group 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.