Chemistry Revision 2k15

Chemistry Revision 2k15

1. Bonds

2. Atoms, Elements and Compounds

   • Atoms
     • Very small
     • Nucleus
     • Electrons and protons and neutrons
     • The different energy levels for the electrons are called energy shells. Each shell can hold a limited number of electrons.
   • Elements
     • Made up of one kind of atoms only
       • Example- Hydrogen
   • Compounds
     • Made up of more than one kind of atom
       • Example-H2O
   • The mass of a proton is essentially the same as that of a neutron, but 1,840 times greater than the mass of an electron.

3. Acids and alkalis