Isotopes

• Every atom of the same element will contain an identical number of protons (the same atomic number). But atoms of the same element can have different numbers of neutrons: these atoms are known as isotopes. Hydrogen has 3 isotopes:
• Protium

  • Protium is a hydrogen atom with 1 proton and 0 neutrons.
  • 99.98% of hydrogen atoms are protium.
  • It is used in hydrogen fuel cells and the production of plastics.

  
• Deuterium

  • Deuterium is a hydrogen atom with 1 proton and 1 neutron.
  • Around 0.02% of hydrogen atoms are deuterium.
  • It is used in nuclear fusion.

  
• Tritium

  • Tritium is a hydrogen atom with 1 proton and 2 neutrons.
  • It is very rare.
  • It is used in thermonuclear fusion weapons.

  
• Isotopes

  But atoms of the same element can have different numbers of neutrons: these atoms are known as isotopes.

  E.g. Hydrogen has three different isotopes:

  • Protium
  • Deuterium
  • Tritium