Isotopes are atoms of the same element with the same number of protons but different numbers of neutrons.
Chemical
Properties
IDENTICAL.
Chemical reactions involve electrons. Since isotopes have the same electron configuration, they react in exactly the same way.
Physical
Properties
DIFFERENT.
Physical properties (e.g., density, boiling point, rate of diffusion) depend on mass. Since isotopes have different masses (A), these properties vary.
Example: Hydrogen Isotopes
H
Protium
0 neutrons
99.98%
D
Deuterium
1 neutron
Heavy Water
T
Tritium
2 neutrons
Radioactive