1. Life on the Edge

2. Procedure
Get into groups of 4
Answer questions 1-7

3. Discuss What do atoms in group 1 have in common?
-same number of electrons in the outer level

4. Valence Electrons!
Atoms in the same column have the same number of valence electrons.
Valence electrons: atoms in the highest energy level/shell

5. Discuss
How does the number of electrons change as you move from atom to atom across a row?
- the number of electrons increase by 1

6. Discuss
3. How does the arrangement of the electrons change as you move down the columns?
-gets bigger!
-one more shell is added

7. Energy Levels
The period number of the row an element is located in, gives you the number of energy levels*
Exceptions: junk in the middle! And junk below

8. Discuss
How many shells of electrons does Br have? How many electrons are in Br’s outermost shell?
-4 shells
-7 outermost electrons
BONUS: What do we call the outermost 7 electrons?!

9. Discuss
Predict the number of electrons in iodine’s outermost shell. Explain.
-7!
-All elements in the same column have the same number of outermost electrons
BONUS: What do we call the outermost electrons?!

10. Discuss
What happens to the electron count and the number of shells when you move from Ne to Na?
-one more electron!
-one more shell!

11. Discuss
What group is Tl in? How many electrons will it have in its outermost shell?
-3A (13)
-3!

12. PERIODIC TABLE Columns = groups Groups Rows = periods Periods
Same number of valence electrons
Rows = periods
Periods
Same energy level (except between the periodic table goal post)

13. Terms Valence shell: outermost shell of an atom
Valence electrons: electrons in the valence shell
Core electrons: all electrons except valence electrons (inner electrons)