Atomic structure

• Atoms


  Tiny, difficult to see particles that make up all matter
• Atoms contain protons, neutrons and electrons
• Atoms


  • Have a diameter of about 0.1 nanometres (around 1 x 10^-10 m)
  • There are a few different models of the atom, but chemists tend to use the Bohr model
• Nucleus


  The central part of the atom
• Nucleus


  • Contains protons and neutrons
  • Has a radius of around 1x 10^-14 m (around 10,000 times smaller than the radius of the atom)
  • Has a positive charge because of the protons
  • Almost all the mass of the atom is concentrated in the nucleus
• Subatomic particles


  • Protons
  • Neutrons
  • Electrons
• Proton


  Positively charged subatomic particle
• Neutron


  Subatomic particle with no charge
• Electron


  Negatively charged subatomic particle that moves around the nucleus
• The number of protons equals the number of electrons in an atom, giving it no overall charge
• Silicon is an element because it consists of atoms that all have the same number of protons