What Is the Charge of Water? A Look at Its Polarity and Net Charge

A water molecule has a net charge of zero. Its two hydrogen atoms and one oxygen atom together have 10 protons and 10 electrons, so their positive and negative charges balance. Water is electrically neutral overall.

Its charge is not spread evenly, though. Oxygen attracts the shared electrons more strongly than hydrogen does. This leaves the oxygen end with a partial negative charge, written δ−, and the hydrogen ends with partial positive charges, written δ+ Encyclopaedia Britannica. These are partial charges, not full charges like the charges on ions.

That difference explains why water can be neutral and still behave as a polar molecule. “Neutral” describes its total charge. “Polar” describes how that charge is distributed.

Why water is polar

Water’s shape matters as much as the difference in how oxygen and hydrogen attract electrons. The molecule is bent, with oxygen between the two hydrogen atoms. The partial charges therefore do not cancel out: the oxygen side is more negative, while the hydrogen side is more positive. Together, this separation of charge gives water a dipole LibreTexts.

A molecule with polar bonds is not necessarily polar overall. Carbon dioxide, for example, has polar bonds, but its linear shape means the bond dipoles cancel. Water’s bent shape prevents that cancellation.

What water’s polarity does

The partly positive hydrogen atoms in one water molecule are attracted to the partly negative oxygen atoms in nearby molecules. This attraction is called hydrogen bonding Encyclopaedia Britannica. Hydrogen bonds help explain why water molecules attract one another and why water takes substantial energy to boil.

Water’s polarity also helps it dissolve many ionic and polar substances. In salt water, water molecules orient around the ions: oxygen ends tend to face sodium ions, and hydrogen ends tend to face chloride ions USGS. The ions disperse through the water, though the water molecules themselves remain neutral.

A charged object can also deflect a thin stream of water. Its electric field affects the orientation of water’s dipoles. This is another way to see that a neutral molecule can respond to an electric field because its charge is unevenly distributed.

One example: checking a water molecule’s charge

For one H₂O molecule:

• The oxygen atom has 8 protons.
• Each of the two hydrogen atoms has 1 proton, giving 2 more.
• The molecule therefore has 10 protons. A neutral water molecule also has 10 electrons.

The total positive and negative charges cancel, so the molecule’s net charge is zero. Its bent shape and uneven electron distribution make it polar, but do not give it a net charge.

Molecules, pure water, and solutions

The phrase “charge of water” can refer to a molecule or to a sample of liquid. A single H₂O molecule is neutral. A sample of pure water is also neutral overall, although a small fraction of water molecules transfer protons to other water molecules. This produces hydronium ions, H₃O⁺, and hydroxide ions, OH⁻. They form in equal numbers in pure water, so their charges balance LibreTexts.

Dissolved salts add ions to a water sample. Those ions can move through the liquid and carry electric current; the H₂O molecules are not the source of a net charge. Water with dissolved ions conducts electricity better than very pure water USGS.

So, if the question is whether a water molecule is positively or negatively charged, the answer is neither: its net charge is zero. If the question is whether water has separated positive and negative regions, the answer is yes: it is polar.

Key Takeaways

• A water molecule has a net charge of zero because it has 10 protons and 10 electrons.
• Water is polar: oxygen has a partial negative charge, and the hydrogen atoms have partial positive charges.
• Water’s bent shape keeps its bond dipoles from cancelling.
• Polarity helps water form hydrogen bonds and dissolve ions and other polar substances.
• Dissolved ions, along with small amounts of hydronium and hydroxide in pure water, help water conduct electricity.