In the centre of the atom is the nucleus,
made up of equal numbers of protons and neutrons.


  • matter is made from small particles called atoms – they are the building blocks of the Universe.
  • atoms are so extremely small that one million could fit on the full stop at the end of this sentence. (photo)
  • atoms are the smallest identifiable piece of a chemical element. (diagram: Size of atoms)
  • many different atom as there are elements. (The Periodic Table of the Elements: poster )
  • atoms are mostly empty space with tiny sub-atomic particles (sub-atomic means “smaller than an atom”).  (diagram)
  • the core of an atom is the nucleus – made two kinds of sub-atomic particle; protons and neutrons.
  • swooshing around the nucleus are even tinier particles called electrons. (diagram)
  • electrons have a negative electrical charge; protons have a positive charge – electrons are held to the nucleus by electrical attraction. (diagram: electrons / electrical attraction)
  • under certain conditions – one atom can be split into more than 200 kinds of short-lived sub-atomic particle of nucleus are made from various tiny particles called quarks.  (diagram)


Did you know?

  • Quarks – came into existence when the Universe has existed for less than one second.  (diagram: quarks / From Quarks to Earth today (poster)

Back to The Universe page.


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