Dynamical behavior of chemical reactivity indices like electronegativity, hardness, polarizability, entropy, electrophilicity and nucleophilicity indices and uncertainty product is studied within a quantum fluid density functional framework for the interactions of a helium atom in its ground and excited electronic states with monochromatic and bichromatic laser pulses with different intensities. Time dependent analogues of various electronic structure principles like the principles of electronegativity equalization. maximum hardness, minimum polarizability and maximum entropy have been found to be operative. Insights into the variation of intensities of the generated higher order harmonics on the color and intensity of the external laser field are obtained.