Inductive and resonance effects of different substituents (CH3, Cl, NH3, CN, NO2) on the reactivity of the nitrogen and oxygen centers of several saturated and unsaturated hydroxylamine derivates toward hard and soft electrophiles are analyzed in terms of various conceptual DFT based descriptors calculated using B3LYP/6-311G** method. In most cases, the +/-I and +/-M effects are correctly described by these descriptors. The way the substituent effect dies down as the distance between the substituent and the active center increases is also analyzed. It is observed that more than one effect is to be considered to properly understand the effect of a substituent on reactivity.