Dynamics of chemical reactivity parameters like electronegativity, hardness, polarizability, electrophilicity index etc. has been studied by solving a generalized nonlinear Schrodinger equation for typical time - dependent problems like ion - atom collisions and atom - field interactions. Dynamical variants of popular electronic structure principles like electronegativity equalization principle, HSAB principle,maximum hardness principle and minimum polarizability principle are now understood better.