What’s in an atom
Particle
Electrons
Relative
Mass
Charge Where
When
Who
Negligible
Negative
~0
-1
Shells
1897
Thompson
Nucleus
1911
Nucleus
1932
Rutherford
(Gold foil
experiment)
Chadwick
1911
Rutherford
Proton
1
Positive
Neutron
1
Neutral
Nucleus
Sum of P + N
+1
0
+