Hydrogen is a non-metal. Hydrogen is a colourless, odourless and tasteless gas that is the most abundant element in the known universe. It is the lightest and simplest having only one proton and one electron.
- Although hydrogen has an ns1 electron configuration just like alkali metals, it is still not metal because it varies greatly from the alkali metals as it forms cations (H+) more reluctantly than other alkali metals.
- Because hydrogen is a nonmetal and forms H–(hydride anions), it is placed above the halogens in the periodic table.
- Hydrogen also forms H2dihydrogen like halogens.
- However, hydrogen is very different from halogens. Hydrogen has a much smaller electron affinity than halogens.