Question

when two or more atoms differ only in the number of neutrons that each contains, what property or properties change?
a mass and chemical properties
b mass only
c physical and chemical properties
d mass, chemical, and physical properties

Explanation:

Atoms that differ only in neutron number are isotopes. Neutrons contribute to mass but not to chemical properties (determined by protons and electrons). Physical properties like density can change due to mass - change, but chemical properties remain the same.

Answer:

B. mass only