1. Periodic Table Determining Shells and Valence Electrons
images are from

2. Periods Each row is called a “period”
The elements in each period have the same number of shells
1st Period = 1 Shell
2nd Period = 2 Shells
3rd Period = 3 Shells
4th Period = 4 Shells

3. Groups Group 8 = 8 electrons Group 1 = 1 electron
Except for He, it has 2 electrons
Group 2 = 2 electrons
Each column is called a “group”
3, 4, 5, 6, 7
Each element in a group has the same number of electrons in their outer orbital, also known as “shells”.
The electrons in the outer shell are called “valence electrons”

4. Transition Metals
Transition Metals have slightly different rules for shells and valence electrons.
This is something you will learn about in your Chemistry course later on.

5. 2nd Period = how many shells?
Determine the number of shells and the number of valence electrons for:
Carbon - C
2nd Period = how many shells?
4th Group =
How many valence
electrons

6. Determine the number of shells and the number of valence electrons for:
Sodium - Na
3rd Period = ?
1st Group = ?

7. Write your answers on your handout.Ne
Name the element.
Number of shells ?
Valence electrons ?

8. Write your answers on your handout.Ne
Name the element.
Number of shells ?
Valence electrons ?
Neon
2nd Period = 2 shells
8th Group = 8 valence
electrons

9. Write your answers on your handout.
Name the element.
Number of shells ?
Valence electrons ?

10. Write your answers on your handout.
Name the element.
Number of shells ?
Valence electrons ?
Hydrogen
1st Period = 1 shell
1st Group = 1 valence
electron

11. Write your answers on your handout.Be
Name the element.
Number of shells ?
Valence electrons ?

12. Write your answers on your handout.Be
Name the element.
Number of shells ?
Valence electrons ?
Beryllium
2nd Period = 2 shells
2nd Group = 2 valence
electrons

13. Write your answers on your handout.
Name the element.
Number of shells ?
Valence electrons ?

14. Write your answers on your handout.
Name the element.
Number of shells ?
Valence electrons ?
Sulfur
3rd Period = 3 shells
6th Group = 6 valence
electrons

15. Write your answers on your handout.K
Name the element.
Number of shells ?
Valence electrons ?

16. Write your answers on your handout.K
Name the element.
Number of shells ?
Valence electrons ?
Potassium
4th Period = 4 shells
1st Group = 1 valence
electron

17. Write your answers on your handout.He
Name the element.
Number of shells ?
Valence electrons ?

18. Write your answers on your handout.He
Name the element.
Number of shells ?
Valence electrons ?
Helium
1st Period = 1 shell
8th Group = 2 valence
electrons
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.

19. The valence electrons travel further from the nucleus and have a higher energy

20. Because these electrons are further away from the nucleus, the attraction is weaker and more easily broken
This is why the valence electrons determine the behavior or reactivity of an element with other elements

21. going…going…