Electrons

Electrons

1. There are the same number of electrons as protons in an atom.

2. Electrons in the same shell have the same energy.

3. The nearer the nucleus, the lower the energy of the electrons. Electrons always go to the lowest energy shell they can.

4. Number of electrons in the outer shell = Group in the periodic table

5. Number of shells = Period in the periodic table

6. Elements with the same number of elements in their outer shell react in a similar way. This is called periodicity.