What is the molecular composition of water?

Water, a vital compound for all known forms of life, is composed of two hydrogen atoms bonded to one oxygen atom. This molecular formula is expressed as H₂O. The arrangement is crucial because the unique properties of water, including its high heat capacity, surface tension, and ability to dissolve many substances, arise from the molecular structure and the angles formed between the hydrogen atoms and the oxygen atom.

In the case of the correct answer, the presence of two hydrogen atoms allows for the formation of stable covalent bonds with a single oxygen atom, creating the familiar structure of water. This specific composition is key for water's role in biological systems, its behavior as a solvent, and its interactions in various chemical reactions.

The other combinations listed do not accurately reflect the known and stable structure of water, highlighting the importance of correct molecular composition in understanding chemistry and biology.