Counting Subatomic Particles

Mass Number vs. Atomic Number Atomic Mass or Mass Number Sum of the protons and neutrons in the nucleus of an atom Atomic mass unit or amu Atomic Number Equals the number of protons In a neutral atom, protons = electrons

Counting Subatomic Particles Atomic Mass = Protons + Neutrons The atomic mass must be given. The atomic mass on the periodic table is an AVERAGE atomic mass. Atomic Number = Number of Protons All neutral atoms will have the same number of protons and electrons.

Finding Atomic Mass and Number Element Name Atomic Number Element Symbol Average Atomic Mass

Bromine - 80 Atomic mass = 80 amu Atomic number = 35 Protons = 35 Electrons = 35 Neutrons = 45 80-35 = 45

Sulfur - 32 Atomic mass = 32 amu Atomic number = 16 Protons = 16 Electrons = 16 Neutrons = 16 32-16 = 16

Nickel- 59 Atomic mass = 59 amu Atomic number = 28 Protons = 28 Electrons = 28 Neutrons = 31 59-28 = 31

Oxygen - 16 Atomic mass = 16 amu Atomic number = 8 Protons = 8 Electrons = 8 Neutrons = 8 16-8 = 8

Copper - 64 Atomic mass = 64 amu Atomic number = 29 Protons = 29 Electrons = 29 Neutrons = 35 64-29 = 35