Question

Name the elements which form water.
How will you justify that water is a compound? 

Answer 1

The elements which form water are Hydrogen and oxygen.
Justification: Water has entirely different properties (i.e. is a liquid, extinguishes fire) from the elements it is made up of i.e. Hydrogen a gas catches fire oxygen a gas supporter of combustion.

1. Energy is needed to form water on combining O2 with H2.
2. We can not separate the constituents of water by simple physical means.