3 Main Categories of the Periodic Table

• Metals – Everything to the left of the stair step line

• Non-Metals – Everything to the right of the stair step line

• Metalloids – The atoms along the stair steps

The periodic table is FULL of patterns.

• If you know the patterns, you can use it to find information quickly about the elements

• The two patterns we are going to review are the periods and the group numbers

Let's start with the periods

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• Periods are the horizontal rows that go across the table.

• Each new period is a new electron shell. All of the elements in a period have the same number of electron shells.

• Moving from left to right, each element has more electrons, & the elements need more space for those electrons

Now let's talk groups!

• Groups (also called families) are the vertical (up and down) columns on the periodic table

• There are 18 groups on the periodic table BUT only groups 1 and 2 and 13-18 follow any sort of pattern.

• The group number can help you quickly figure out the number of valence electrons.

The Group Pattern

• Group 1 has 1 valence electron

• ​Group 2 has 2 valence electrons

• Group 13 has 3 valence electrons      

• Group 14 has 4 valence electrons      

• Group 15 has 5 valence electrons      

• Group 16 has 6 valence electrons      

• Group 17 has 7 valence electrons      

• Group 18 has 8, except for Helium, which has 2 (but all have a full outer shell)