1. Unit 3 page 7
Do Now: What are atoms considered the building blocks of
matter?

2. Term Definition
Proton
Neutron
Electron
Atomic
Number
Mass
Number
Atomic
Mass

3. Term Definition
Proton A particle found the in the atomic nucleus that has a positive
electrical charge
Neutron A particle found in the atomic nucleus that has no charge
Electron A negatively charged particle that orbits around the nucleus
Atomic Number of protons
Number
Mass Total number of protons and neutrons in an atom’s nucleus
Number
Atomic Mass The average mass of a sample of atoms of that element found
in nature

4.  Color the diagram according to your key

5.  Label the diagram with: Atomic Mass, Mass Number,
Symbol

6. Symbol
# of Protons
# of Neutrons
# of Electrons
Atomic Number
Mass Number
Atomic Mass (round to nearest 10th)

7. Symbol Na
# of Protons 11
# of Neutrons 12
# of Electrons 11
Atomic Number 11
Mass Number 23
Atomic Mass 22.990