Hydrogen is a nonmetal.
However, hydrogen differs from metals in several ways.
1. It is reluctant to form cations.
The alkali metals lose electrons easily to form cations.
But the ionization energy of hydrogen is 2.5 times that of lithium, the alkali metal with the highest ionization energy.
2. Elemental hydrogen consists of
Hydrogen atoms join by covalent bonds to form
The molecules are attracted to each other by weak London dispersion forces.
Metal atoms are attracted to each other by metallic bonds.
3. Hydrogen forms covalent compounds.
The bonds in these compounds are covalent.
Most of the compounds of Group 1 metals are ionic.
For example, sodium chloride consists of
4. Hydrogen forms hydride ions.
Hydrogen forms compounds like
In these compounds, the hydrogen exists as the hydride ion,
Theoretical calculations predict that hydrogen can behave like a metal at a pressure of 500 000 atm.
It may exist as a metal in the interiors of large planets like Jupiter and Saturn.