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 In an there are available spaces in the cloud for electrons. They can be called levels, shells and orbitals(We only draw it like this, but they move)  The first ring can hold up to 2 electrons.  The second and third rings can hold up to 8 electrons  In an uncharged atom, the protons equal the electrons  The picture shows the available spots that electrons can go

Valence Electrons- A valance electron is only looking at the last ring on the outside

This is showing 1

Lewis Dot Diagrams-

Because each element has 1 valance electron, instead of drawing the

entire atom we can now write the elements symbol with dots that represent how many electrons there are.

All in group 1 have 1 valence electron, so they all have 1 dot.

Notice that the elements drawn above show the electrons for each atom. They ALL have 1 valence electron. The electron in the outside shell. If every atom in group 1 was drawn, they would ALL have 1 valence electron in the outermost shell.

Every element in group 2 has 2 valence electrons! Instead of drawing the entire atom model, you can write the element symbol with at dot at the top and a dot at

the bottom of the symbol. This represents the valence electrons (the electrons on the outer most shell).

This is an example of 2 of the elements in group 2.

Every element in group 2 has 2 valence electrons!

The pattern continues for group 13 through group 18. It doesn’t work for the section in the center

All elements in group 13 will have 3 dots, exactly like you see on B

All elements in group 14 will have 4 dots, exactly like you see on C

All elements in group 15 will have 5 dots, exactly like you see on N

All elements in group 16 will have 6 dots, exactly like you see on O

All elements in group 17 will have 7 dots, exactly like you see on F

All elements in group 18 will have

8 dots, filling all 8 places

Helium only has 2 valence electrons, but 2 is full on the 1st level so it fits with this group.