Hmm...not too sure about chemical stability or chemical reactivity. Do you mean kinetics and thermodynamics?
Typically when you look at thermodynamic stability you look at the stability of the products (ie things like more substituted alkenes are thermodynamically more favored than less substituted alkenes).
When you look at kinetics, you want to look at more of the stability of the intermediates, i.e. the energy of activation. Lower activation energies mean that the product is more kinetically favored and you will get more of it b/c it is the kinetic product, formed faster.
Note however that the kinetic and thermodynamic product are not necessarily the same, but they can be. A product can be kinetically favored but thermodynamically not. Typically the latter are favored at higher temperatures when most rxns are reversible. The former are favored at lower temperatures where rxns are not so reversible and activation energy is more key b/c once you get the product, you are kind of stuck with it.
A good example of these principles would be electrophilic attack on conjugated dienes. Take a look at the Energy vs. rxn coordinate diagram and you will see what I mean.
ChemBuddy | 
Chem Reddit | 
Topic: Chemical stability,thermodynamic stability and chemical reactivity (Read 5653 times)