1. Warm Up 1/7 - Protons, Neutrons, Electrons5 B
Boron 11 11 Na
Sodium 22 17 Cl
Chlorine 35 2 He
Helium 4
a. For each element:
How many Protons?
Electrons?
Neutrons?
b. For each element:
Draw a Bohr Model

2. Remember the rules for Bohr Models
Inner shell – 2 Electrons
Middle shell – up to 8 electrons
Outer shell – up to 8 electrons

3. Valence Electrons
Valence electrons are the electrons in the outside electron shell of an atom.
Valence electrons are important in how a element reacts with other elements.
Elements which have eight valence electrons (noble gases) are inert and they do not tend to create chemical reactions with other elements.
The number of valence electrons determines how an atom reacts with other atoms.

4. Nobel Gasses Have 8 Valance Electrons
Nobel Gasses do not react, or form bonds, with other elements.

5. The Octet Rule
The octet rule that states that atoms tend to combine in such a way that each atom has eight electrons in its outer (valence) shell, giving it the same stable electron configuration as a noble gas.

6. . What atoms make up a molecule of water?
H2O

7. Draw a Bohr model of Hydrogen and A Bohr model of Oxygen
The number of valence electrons determines how atoms react with other atoms.
Draw a Bohr model of Hydrogen and A Bohr model of Oxygen 1 H
Hydrogen 8 o
Oxygen 16

8. The number of valence electrons determines how atoms react with other atoms.
Try this!
Draw three Bohr models showing how one oxygen atom forms bonds with two hydrogen atoms.
Hint: Atoms can share electrons!
Have students draw their model on the board

9. Notice the valence electrons
A covalent bond is a chemical bond that involves the sharing of electron pairs between atoms.

10. Electrolysis of Water
Running an electrical current through water can separate the hydrogen and oxygen atoms.

11. How will we know we separated the hydrogen and oxygen of the water molecule?
Remember the Hindenburg?

12. Lab Materials & Set Up
Video