1. Valence Electrons & Bohr Diagrams

2. Atomic Structure
Atoms have a nucleus that contains Protons and Neutrons
Electrons are contained in shells that surround the nucleus
Protons have a positive charge
Electrons have a negative charge
Neutrons are Neutral

3. Valence Electrons Electron Shell Number of Electrons 1 2 8 3 4 18 5 6
Each electron shell can hold a certain number of electrons
Electron shells are filled from the inside out
Electron Shell
Number of Electrons 1 2 8 3 4 18 5 6 32 7

4. Stable Elements
An element with a full valence shell is a happy element 
For two atoms to join together atoms must gain, lose or share electrons
Elements with full valence shells do not easily gain or lose electrons

5. Becoming An Ion
When atoms gain or lose electrons they become positively or negatively charged
An atom with a charge is called an Ion
Example: NaCl

6. Bohr Models
Niels Bohr created a visual model of the atom to make them easy to understand
A Bohr Model contains a central nucleus surrounded by electron shells
For each model you state the number of protons and neutrons in the nucleus and draw a dot on the electron shells for each electron