A substance composed of three atoms, particularly two hydrogens and one oxygen. Oxygen is located in the middle of the bond, while the two hydrogens branch out from it separately. Here is a model: H--O--H. This substance is required by all living organisms.
First of all you need to attend a basic literature class because your question is grammatically incorrect. And secondly it's questions like these that make me realize that I am actually not as stupid as I think I am because when times get rough at least I can go to bed knowing that I know what water is.
It means H-hydrogen, O-oxygen. Hydrogen has 1 valency,and Oxygen has 2 valency ,and there has to be 2 hydrogen atoms,and 1 oxygen to be equal ,so H2O,H2 2 atoms of hydrogen,and O 1 atom of oxygen -again H has 1 valency ,and O has 2,so 1 times to is 2 valency and 2 times on is 2 valency(yo'u will learn it on kemistry