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Isotopes

Physics: Cambridge International GCSE Supplement, topic 5.1.6

Isotopes

Atoms of an element always have the same number of protons (atomic number). A Hydrogen atom must have 1 proton. However, many elements have atoms with different numbers of neutrons. We call these different isotopes. Hydrogen can form three isotopes.

Protium

Protium

  • Protium is a hydrogen atom with 1 proton and 0 neutrons - 1H. It has a mass number of 1 and 99.98% of Hydrogen atoms are Protium. It is used in Hydrogen fuel cells and the production of plastics.
Deuterium

Deuterium

  • Deuterium is a hydrogen atom with 1 proton and 1 neutron - 2H. Around 0.02% of Hydrogen atoms are Deuterium and it is used in nuclear fusion.
Tritium

Tritium

  • Tritium is a hydrogen atom with 1 proton and 2 neutrons - 3H. It is very rare and is used in thermonuclear fusion weapons.

Test yourself on Isotopes

  • Hydrogen has one proton. Deuteurium and tritium are both isotopes of hydrogen.
    How many protons do they have?

  • What do we call atoms of the same element with the same number of protons, but a different number of neutrons?

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