Atoms

Atoms

1. atoms are the building blocks of everything

   • they're amazingly tiny - you can only see them with an incredibly powerful electron microscope

2. the nucleus

   • Its in the middle of the atom
     • it contains protons and neutrons
       • it has a positive charge because of the protons
         • Almost the whole mass of the atom is concentrated in the nucleus
           • but size wise its tiny compared to the rest of the atom

3. the electrons

   • move around the nucleus
     • they're negativly charged
       • they're tiny, but they cover a lot of space
         • the volume of their orbits determines how big the atom is
           • they have virtually no mass
             • they're arranged in shells around the nucleus
               • these shells explain the whole of chemistry

4. Particals

   • Protons are heavy and positivly charged
   • neutrons are heavy and neutral
   • electrons are tiny and negatively charged

5. Number of protons EQUALS number of electrons

   • neutral atoms have no charge overall
     • the charge on the electrons is the same size as the charge on the protons - but opposite (ones negative ones positive)
       • this means the number of protons always equals the number of electrons in a neutral atom
         • if some electrons are added or removed, the atom becomes charged and then is an ion
           • the number of neutrons isn't fixed but is usually about the same as the number of protons

6. Each element has a different number of protons

   • it's the number of protons in an atom that decides what the element is
     • for example, any atom of the element helium will have 2 protons - and any atom with two protons will be a helium atom
   • elements all have different properties from each other due to the differences in there atomic structure

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