reactivities

noun

1. the quality or condition of being reactive.
2. Chemistry. the relative capacity of an atom, molecule, or radical to undergo a chemical reaction with another atom, molecule, or compound.
3. Physics. a measure of the deviation from the condition at which a nuclear reactor is critical.
4. Immunology. the ability of an antigen to combine with an antibody.

n.

1. The property of reacting.
2. The process of reacting.