structure of the atom

• Atom


  The smallest part of an element that can exist
• Structure of an atom

  • Central nucleus containing protons and neutrons
  • Surrounded by electrons in shells
• Nucleus


  The central part of an atom, containing protons and neutrons, and having most of the mass of the atom
• Electron


  Subatomic particle with a negative charge and a negligible mass relative to protons and neutrons
• The nucleus is very small compared to the atom as a whole, and the diameter of a nucleus can be 100,000 times less than the diameter of an atom
• Most of an atom is empty space
• Subatomic particles


  • Protons
  • Neutrons
  • Electrons
• Proton


  Subatomic particle with a positive charge and a relative mass of 1
• Neutron


  Uncharged subatomic particle, with a mass of 1 relative to a proton
• Relative mass


  The number of times heavier a particle is, compared to another
• The mass of electrons is very small compared to protons and neutrons, and most of the mass of an atom is concentrated in its nucleus
• Protons and electrons have opposite electrical charges
• Protons are positive, and neutrons are neutral