The Periodic Table

The Periodic Table

1. The bottom number is the atomic number.

   • Number of protons
     • The number of protons is the same as the number of electrons
   • Always smaller than the mass number

2. The top number is the mass number

   • This is the total number of protons and neutrons

3. The vertical columns are called groups and are numbered at the top

   • All of the elements in a group have the same number of electrons in their outer shell
     • E.g All the elements in Group 2 have 2 electrons in their outer shell

4. The red line separates metals and non-metals

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