Water: Structure, Polarity, and Hydrogen Bonding

Water composition

• Water is made of two hydrogen atoms and one oxygen atom. The chemical formula is H_2O.
• In each water molecule, the hydrogen atoms share electrons with the oxygen atom.
• This type of connection is called a covalent bond.

Covalent bonds in water

• The oxygen atom pulls on the shared electrons more strongly than the hydrogen atoms.
• This causes the electrons to spend more time near the oxygen.

Polarity of water

• As a result, the oxygen end of the molecule becomes slightly negative, and the hydrogen ends become slightly positive.
• These slight charges make water a polar molecule.
• Denote charges with partial charges: \delta^- on oxygen and \delta^+ on hydrogens.

Hydrogen bonding

• Because of polarity, water molecules are attracted to each other.
• The positive end of one molecule is pulled toward the negative end of another. This attraction is called a hydrogen bond.
• One water molecule can form hydrogen bonds with several other water molecules.

Significance and properties

• Hydrogen bonds are weaker than covalent bonds, but they still affect how water behaves.
• These bonds help explain why water has properties that are different from many other substances.
• Water's structure is the reason it plays such an important role in living systems and on Earth.

Additional notes

• The page appears to include a label "δ Covalent Bond 8" at bottom; it may be a figure label, not content.