Position of hydrogen in periodic table:

Hydrogen is the first element of the periodic table. Its atomic number is 1, which indicates the presence of only one electron in the atom of hydrogen. This electron is present in its first shell. Hydrogen resembles both alkali metals (group I A) as well as halogens (group VII A) therefore its position is said to be anomalous.

Some Basic Features of Hydrogen

 

Symbol	H
Molecular formula	H2
Atomic number	1
Mass number	1
Atomic mass	1.008
Molecular mass	2
Electronic configuration	1
Valency	+ 1 or -1
Isotopes of Hydrogen	11H Protium
	21H Deuterium
	31H Tritium