year 9 chemistry recap

year 9 chemistry recap

1. what are they made of?

   • Atoms
     • descriptionsof atoms have changed over time
     • structure
       • nutrons
         • protons
           • mass of approx .1AMU
             • number of P's
           • positily charged
       • electrons
         • negatively charged
         • orbit the atoms
         • remain in the orbit around atoms due to attractions for positily charged protons
           • changing the number of a gives the atoms a charge -called an iroi

2. chemical reactions

   • signs of a chemical reactions