Covalent Bonds
What are Covalent Bonds?
- Covalent bonds occur when atoms share electrons.
- This typically occurs between non-metal atoms.
- Each shared pair of electrons forms a single covalent bond. Two or three shared pairs form a double or triple covalent bond respectively.
- In covalent bonding, each atom contributes at least one electron to the shared pair.
Properties of Covalently Bonded Substances
- Substances that contain covalent bonds can exist as simple molecules or giant structures.
- Simple molecular substances have low melting and boiling points due to the relatively weak forces between molecules.
- Giant covalent structures such as diamond and silicon dioxide have very high melting and boiling points because breaking the numerous covalent bonds requires a lot of energy.
- Most covalent substances do not conduct electricity because there are no charged particles free to move.
Examples of Covalent Compounds
- Water (H2O): Oxygen shares a pair of electrons with each hydrogen atom to form two covalent bonds, resulting in a water molecule.
- Methane (CH4): Carbon shares a pair of electrons with each hydrogen atom to form four covalent bonds, creating a methane molecule.
- Diamond: Each carbon atom forms four covalent bonds with other carbon atoms, creating a giant covalent structure.
Key Points of Understanding
- Understand the principle of electron sharing in covalent bonding.
- Know the different properties of simple and giant covalent structures.
- Be able to identify examples of covalent compounds and explain their electron sharing arrangements.