1. All images are from www.Chem4kids.comwww.Chem4kids.com Determining Shells & Valence Electrons

2. Periods Each row is called a “period” The elements in each period have the same number of shells www.chem4kids.com

3. Groups Each column is called a “group” Each element in a group has the same number of electrons in their outer orbital, also known as “shells”. Except for He, it has 2 electrons The electrons in the outer shell are called “valence electrons” www.chem4kids.com

4. Transition Metals Transition Metals have slightly different rules for shells and valence electrons. This is something you will learn about in High School Chemistry. www.chem4kids.com

5. Determine the number of shells and the number of valence electrons for: www.chem4kids.com

6. Determine the number of shells and the number of valence electrons for: www.chem4kids.com

18. Helium is the exception in Group 8. Since it has just one shell, that shell can only fit 2 electrons instead of 8. It is in this group because all the elements have a full outer shell.