Question

Why hydrogen and oxygen are consider as a element whereas water is a compound

Answer 1

because water is a combination of hydrogen and oxygen.

2H2+O2----2H2O

2 molecules of the element hydrogen and 1 molecule of element oxygen combime to form 2 water molecules.

Hydrogen(H) and Oxygen(O) are elements because they can't be broken down further by any physical means.(exception: nuclear fision)

Answer 2

Answer:

Water is a compound because hydrogen and oxygen have reacted to form a new substance viz. water whereas in a mixture there is no reaction and the individual gases retain their identity;in short compound is chemical combination whereas mixture is the physical combination of the species taking part....