1. Parts of the Atom

2. Protons Positive charge Located in the nucleus
Contribute to the atomic mass
Have a mass of 1 amu
Number of protons = the ATOMIC NUMBER
The number of protons identifies the element (CANNOT BE CHANGED)

3. Electrons Negative Charge Outside of the nucleus
1/2000 the mass of a proton
Does not contribute to the mass
Only particle that can leave the atom (ion formation)
Fundamental particle for all chemical processes

4. Neutrons Located in the nucleus No charge Mass of 1 amu
Combine the number of protons and neutrons to calculate the atomic mass
Balance the +/- interactions between the protons and electrons

5. What is in the nucleus? Central core of all atoms
Center of mass and dense
+ charge
All protons and neutrons are in the nucleus