The Periodic Table

• Elements with similar properties form columns
• Verticle columns are called groups
• Elements in a group have the same number of electrons on the outer shell
• The elements in group 0/8 are noble gases - stable and unreactive

• The top number is the mass number - total number of protons and neutrons
• The bottom number is the atomic number - number of protons=number of electrons

To find the number of neutons subtract atomic number from mass number