Covalent bonds occur when atoms share pairs of electrons to form molecules. Atoms form covalent bonds by sharing unpaired valence electrons, with examples being water (H2O) forming two covalent bonds and molecular oxygen (O2) forming a double covalent bond by sharing two pairs of electrons. Properties of covalent bonds include low melting and boiling points with poor conductivity.

1. Covalent Bonds

2. Covalent Bonds
• Covalent bonds occur when atoms
share electrons.
• Covalent bonds generally form
between nonmetals.
• Atoms that are covalently bonded form
molecules.

3. Covalent Bonds
• Covalent bonds occur at unpaired valence
electrons on the outer shell for each atom.
• Example: H2O has 2 bonds:
Before… After…
H O H O H
H

4. Covalent Bonds
• Covalent bonds create neutral
molecules when they come together.
• How many bonds between 2 atoms?
– Covalently bonded atoms can bond up to 3
times. They cannot exceed 3 bonds
between two atoms.

5. Covalent Bonds
• Double bonds: When two atoms share
two pairs of electrons.
– EX: O2
• Triple bonds: When two atoms share
three pairs of electrons.
– EX: N2

6. Covalent Bonds
• Properties of Covalent Bonds:
– Low melting points
– Low boiling points
– Poor conductor of electricity
– Between nonmetals and nonmetals