TeXes Science Practice Test

What type of bonding occurs between oxygen and hydrogen in water?

1. Ionic bonding

2. Covalent bonding

3. Metallic bonding

4. Hydrogen bonding

The correct answer is: Covalent bonding

In water, the bonding between oxygen and hydrogen is classified as covalent bonding. This occurs because oxygen and hydrogen share electrons to achieve stability in their outer electron shells. Each hydrogen atom contributes one electron, while oxygen contributes its six outer shell electrons, allowing the formation of two covalent bonds—one with each hydrogen atom. Covalent bonds result in the formation of molecules, where atoms are bonded together by the shared pairs of electrons. In the case of water (H₂O), the shared electrons create a polar molecule, meaning that there is an uneven distribution of electron density. Oxygen, being more electronegative, attracts the shared electrons more strongly than hydrogen, resulting in a partial negative charge at the oxygen end and a partial positive charge at each hydrogen end. This polarity leads to unique properties of water, such as its ability to form hydrogen bonds with other water molecules or different polar substances, but it is the covalent bonding that is foundational to the water molecule's structure.