1. Periodic Table Study Guide Determining Shells and Valence Electrons

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 valence e- Group 1 = 1 valence e-
Except for He, it has 2 electrons
Group 2 = 2 valence e-
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 High School Chemistry.

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

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

7. Write your answers in your notebook.Ne
Name the element:
Atomic number:
Number of p+ and n in nucleus:
Number of e- in electron cloud:
Number of e- energy shells:
Valence electrons:

8. Check your answers in your notebook.Ne
Name the element.
Number of shells ?
Valence electrons ?
Neon
2nd Period = 2 shells
8th Group = 8 valence
electrons

9. Write your answers in your notebook.H
Name the element.
Number of shells ?
Valence electrons ?

10. Check your answers in your notebook.
Name the element.
Number of shells ?
Valence electrons ?
Hydrogen
1st Period = 1 shell
1st Group = 1 valence
electron

11. Write your answers in your notebook.Be
Name the element.
Number of shells ?
Valence electrons ?

12. Check your answers in your notebook.Be
Name the element.
Number of shells ?
Valence electrons ?
Beryllium
2nd Period = 2 shells
2nd Group = 2 valence
electrons

13. Write your answers in your notebook.
Name the element.
Number of shells ?
Valence electrons ?

14. Check your answers in your notebook.
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. Check your answers in your notebook.
Name the element.
Number of shells ?
Valence electrons ?
Potassium
4th Period = 4 shells
1st Group = 1 valence
electron

17. Write your answers in your notebook.He
Name the element:
Atomic number:
Number of p+ and n in nucleus:
Number of e- in electron cloud:
Number of e- energy shells:
Valence electrons:

18. Check your answers in your notebook.
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.