Atomic Structure
Parts of the atom


Subatomic Particles
Charge
Mass
               
Proton
+1
1 AMU
                     
Neutron
  0
1 AMU
              

Electron
-1
No Mass   [1/1837 AMU]

Finding the Number of Subatomic Particles
Atomic Number: The number of Protons and Electrons in an atom.  [Whole # on the Periodic Table]
Examples:   Oxygen, O: Atomic # = 8,  8 Protons and 8 Electrons
                    Potassium, K: Atomic # 19, 19 Protons and 19 Electrons
Mass Number:  The number of Protons plus Neutrons in an atom  [Decimal # on the Periodic Table, round the mass number to a whole number, except Chlorine, use 35.5 AMU]
Examples:   Sulfur, S:  Mass # = 32,  16 Protons and 16 Electrons
                  Aluminum, Al:   Mass # = 27,  13 Protons and 14 Neutrons
Neutrons:  Are determined by subtracting the Mass # - Atomic #

   Mass #-     27Al   The Aluminum atom can be represented by the example in bold on the left.
Atomic # -    13

Find the subatomic particles for each isotope:
Isotope
Protons
Neutrons
Electrons
Carbon


Chromium - 52


Zinc - 68


 210 Pb
  82



Answers:
Isotope
Protons
Neutrons
Electrons
Carbon
6
6
6
Chromium - 52
24
28
24
Zinc - 68
30
38
30
 210 Pb
  82
82
128
82