1. CHEMICAL BONDING

2. CHEMICAL CHANGE AKA Chemical Reaction
Occurs when chemical bonds are destroyed and new bonds made.

3. Electron Number and Organization
The number of electrons in an atom can be determined from the atomic number of the element.
Remember?
Atomic # = # of protons = # of electrons =

4. Where are the electrons?
Electrons in an atom are organized in energy levels.
The next slide shows a model of the arrangement of electron in an atom. This model and models like it are useful for counting electrons.

6. Valence Electrons
Most atoms form bonds using only its valence electrons, the electrons in an atom’s outermost energy level. N
TOTAL
ELECTRONS =
VALENCE

8. PERIODIC TABLE & VALENCE ELECTRONS
GROUP 1 = 1 valence electron
GROUP 2 = 2 valence electrons
GROUP 13 = 3 valence electrons
GROUP 14 = 4 valence electrons
GROUP 15 = 5 valence electrons
GROUP 16 = 6 valence electrons
GROUP 17 = 7 valence electrons
GROUP 18 = 8 valence electrons

9. Valence & Bonding # of Valence electrons determines bonding.
Atoms that have 8 valence electrons do not usually form bonds because they are full.
Atoms that have less than 8 valence electrons form bonds because they are not full

11. N N