Elements of life: The atom

Atoms are made up of Protons, Neutrons and Electrons

• Nucleus:
  • most of the mass
  • diameter very small compared to overall size of atom
  • contains protons and neutrons
• Protons:
  • relative mass: 1
  • relative charge: +1
• Neutrons:
  • relative mass: 1
  • relative charge: 0
• Electrons:
  • contained in shells
  • shells make up most of the volume of the atom
  • relative mass: 1/2000
  • relative charge: -1 (negligible)

Nuclear Symbols Show Numbers of Subatomic Particles

• Mass number
  • above the Element symbol
  • tells the…