Hydrogen is the first element in the Periodic Table (thus the element and mass numbers 1) and has the symbol H.


Hydrogen is the lightest element and has one proton (subatomic particle with a positive charge), and one electron (subatomic particle with a negative charge). It has 3 main isotopes:

  • Protium (H) is normal hydrogen. 
  • Deuterium (D) is similar to normal hydrogen, but it has a neutron.
  • Tritium (T) has two neutrons and one proton and electron.

Hydrogen is not toxic, but it is very flammable. It has a stable half-life.

Hydrogen Ions

Hydrogen Ions are protons that are no longer orbited by electrons. Thus, Hydrogen Ions are positively charged.