Atomic Structure and the Periodic Table
This chapter we have discussed different subatomic particles. These particles are protons, electrons and
neutrons. Below you will review and complete exercises over the different types of subatomic particles.
Protons:
If you want to determine the amount of protons in an atom you can look at the atomic number on the
periodic table.
Element Symbol # of protons
Iron Fe 26
Gold Au 79
Sodium Na 11
Oxygen O 8
Uranium U 92
Neutrons:
If you want to determine the number of neutrons in an atom you can look at atomic mass-number on
the periodic table.
Equation you can use to find the number of neutrons:
Element Mass # of protons # of Neutrons
Iron 56 amu 26 30
Gold 197 amu 79 118
Sodium 23 amu 11 12
Oxygen 16 amu 8 8
Uranium 238 amu 92 146
When an atom has a different number of neutrons but the same number of protons it is an isotope.
