1. Unit 2: Atomic Structure

2. The Nucleus Small Dense (a lot of matter in a small volume)
Central region of the atom (the rest of the atom is MOSTLY empty space)

3. Subatomic Particles Table O
Proton
Neutron
Electron
Charge
positive
neutral
negative
Location
In nucleus
Outside nucleus
Size
1 amu (atomic mass unit)
1 amu
1/1836 the mass of a proton
Info
Atomic # = # protons (known as nuclear charge)
Mass # = atomic # (protons) + # of neutrons
When an atom is neutral,
# protons = #electrons

4. Subatomic Particles Protons and Neutrons are also called nucleons
Protons + neutrons = mass # (rounded atomic mass)
Example: carbon has an atomic mass of , so the mass # is 12 (round to tenths if possible)
Protons and neutrons make up most of the mass of the atom
Periodic Table
There is a key at the top of the table
The first oxidation # for each element is referred to as the preferred charge
Always assume an atom is neutral unless told otherwise