THE ATOM

THE ATOM

1. the atom is made up of three sub-atomic particles

   • PROTONS - heavy and positively charged
     • NEUTRONS - heavy and neutral
       • ELECTRONS - have hardly any mass and are negatively charged
         • in reality protons and neutrons are still tiny however they just heavy compared to electrons

2. THE NUCLEUS

   • the nucleus is in the middle of the atom --
   • it contains protons and neutrons
   • it has an overall positive charge due to the protons
   • almost the whole mass of the atom is concentrated in the nucleus
   • compared to the overall atom the nucleus is tiny it has a radius of IO-15m and 10-14m

3. ELECTRONS

   • electrons move around the nucleus in electron shells (in orbit)
   • they are negatively charged
   • they are tiny but their orbitals cover a lot of space
   • electrons virtually have no mass its often zero
   • the volume of their orbitals determines the size of the atom

4. MOLECULES FORM WHEN ATOMS B0ND TOGETHER

   • molecules are made up of two or more atoms
   • molecules can be made of the same element (hydrogen)
     • or different elements (ammonia)
   • simple molecules like atoms are pretty tiny and the bonds are called INTER MOLECULAR BONDS
   • nano-particles are a bit bigger than simple molecules they are typically the size of around 100 atoms joined together
   • they range from 1nm - 100nm in size

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