Bethopedia

An atom is a base unit of matter, and the smallest divisible unit of an element.

Composition

Atoms are comprised of electrons, protons and neutrons:

• Protons (1.673 x 10^-27kg) and Neutrons (1.675 x 10^-27kg):
  • Have a relative weight of 1
  • Form the nucleus, which determines the weight of an atom
  • Protons have a positive charge, neutrons have a neutral charge
• Electrons (6.63 x 10^-34kg):
  • Have a relative weight of 1/1833
  • Form the 'electron cloud', which determines the size of the atom
  • Have a negative charge

Charge

Atoms have the same number of protons and electrons, hence their overall charge is neutral.

Atomic Symbol Representation