Question

Explain why hydrogen is not placed with the halogen in the periodic table.

Answer 1

1. Hydrogen resembles alkali metals as well as halogens.
2. Hydrogen resembles more alkali metals than halogens.
3. The electron affinity of hydrogen is much less than that of halogen atoms. Hence the tendency to form hydride ions is low compared to that of halogens.
4. In most of its compounds hydrogen exists in a +1 oxidation state. Therefore it is reasonable to place the hydrogen in group 1 along with alkali metals as shown in the latest periodic table published by IUPAC.