Question

why do the properties of compounds are different from its constituents

Answer 1

hope this would help you mate,

simply when the elements react , they lose their affinity or negativity

e.g. in the ionic bond of Na+ and Cl- ,
both are harmful substances ,
but due to the bond they neutralize each other and we eat them on daily basis.

Answer 2

It's because compounds are made up of various components which can be se or different and instead of having the properties of all the components it has a unique property which is unlike its constituent.

It may be right......