1_atoms and elements

1_atoms and elements

1. the nucleus

   • the nucleus is really small compared to the whole atom
   • its made up of protons and neutrons

2. the electrons

   • electrons surrond the nucleus in shells (energy levels)

3. protons are positive(+)

4. neutrons are neutral (not charged)

5. electrons are negative (-)

6. the relative masses of parts of an atom

   • protons and neutrons have the same mass (e.g.1 each)
   • the mass of electrons is much smaller (e.g. very ting)

7. there are always be the same number protons as electrons (e.g. 2 positive protons = 2 negitive electrons)

8. the number of protons there are dicides what type of atom it is (e.g. hydrogen = 1 proton, helium = 2 protons)