1. Chapter 1 Activity 7: How Electrons Determine Chemical Behavior

3. Bohr Model—shows the electrons in various energy levels
How many electrons can fit into each energy level??????
Max # e- = 2n2
where n= energy level
Ex. If n=1 (1st energy level), then 2(1)2=
Ex. If n=2 (2nd energy level), then 2(2)2=
Ex. If n=3 (3rd energy level), then 2(3)2=

4. Valence Electrons Valence electrons
Electrons in the outermost energy level of an atom

5. Valence Electrons The Group Number tells us the # of

6. Valence Electrons The Group Number tells us the # of
Valence e- stays the same down a group
Valence e- increases across a period

7. Valence Electrons How many valence electrons does
a Fluorine atom have?
a Magnesium atom have?
an element in the noble gas family have?

8. Things You Need to Now Know
On the periodic table:
The COLUMN or GROUP or FAMILY equals the # of valence electrons (for columns 1,2, 13-18)
The ROW or PERIOD equals the energy level

9. Bohr Models Rutherford focused on describing the nucleus
Bohr focused on describing the location of the electrons
Bohr model (planetary model):
-shows electrons moving in orbits
(energy levels) around the positive
nucleus of the atom.

10. Bohr model for Hydrogen
                                                                                                                                                
Hydrogen is in period 1 = 1st energy level
Hydrogen is the first box in period 1 = 1 electron
Energy level 1
1H 1
# of Electrons in that Energy level

11. Bohr model for Lithium 3Li 2 1
                                                                                                                                                  
Lithium is in period 2 = 2nd energy level
Lithium is the first box in period 2 = 1 electron
Energy level 1
3Li 2 1
Energy level 2
# of Electrons in 2nd Energy level
# of Electrons in 1st Energy level

12. Using What You Now Know
Duet Rule: In forming compounds, atoms tend to gain or lose electrons in order to have two electrons in their first energy level.
Octet Rule: In forming compounds, atoms tend to gain or lose electrons in order to have eight electrons in their outer energy level.

13. Stability
                                                                                                                                                  
Atoms will lose or gain electrons to have a filled outer energy level (duet rule or octet rule).
This fluorine atom has only 7 valence electrons
The octet rule isn’t satisfied
9F 2 7

14. Stability -1 -1 A fluorine atom will try and gain an electron
(7e- + 1e- = 8e-).
With 8e-s, it is now an ANION (-1) with
8 valence electrons
The anion now obeys the octet rule. -1 9F
2 8

15. Stability This sodium atom has 1 valence electron.
The octet rule isn’t satisfied.
11Na 2 8 1

16. Stability
If the sodium atom loses it’s valence electron, it will now have 8 valence electrons.
The octet rule
is satisfied. +1
11Na 2 8

17. Why Atoms React -nonmetals want to keep their valence electrons
Some atoms want to lose valence electrons more than others
-nonmetals want to keep their valence electrons
-metals want to lose their valence electrons

18. Why Atoms React nonmetals want to keep their valence electrons
metals want to lose their valence electrons