Hydrogen does not possess the metallic character under normal conditions because
it has very low ionisation enthalpy
it has very low electron gain enthalpy
it has very high electron gain enthalpy
it has very high ionisation enthalpy
Hydrogen has three isotopes
1. Protium H 11 2. Deuterium H 12
3. Tritium H 13
Protium is the most common isotope of hydrogen with an abundance of 99.98%