Chemical Bonding Explained ｜ Ionic, Covalent and Metallic ｜ GCSE Chemistry

Types of Chemical Bonding

Ionic Bonding

• Occurs between metal and non-metal atoms.

• Example: Sodium (Na) and Chlorine (Cl).

  • Sodium has 1 electron in its outer shell.

  • Chlorine has 7 electrons in its outer shell.

• Atoms seek a full outer shell:

  • Sodium gives its electron to Chlorine.

  • Result: Sodium becomes a positive ion; Chlorine becomes a negative ion.

• The attraction between oppositely charged ions forms ionic bonds.

• Ions arrange into a giant lattice structure.

• Properties:

  • Strong ionic bonds, acting in all directions, lead to high melting points.

Covalent Bonding

• Occurs between non-metal atoms.

• Example: Water (H2O).

  • Oxygen has 6 outer electrons; needs 8.

  • Hydrogen has 1 outer electron; needs 2.

• Atoms share electrons rather than transferring them:

  • Oxygen shares 1 pair of electrons with each hydrogen.

  • Each hydrogen achieves 2 electrons, and oxygen achieves 8.

• The shared pairs create covalent bonds due to attraction:

  • Negative shared electrons attract positive nuclei.

• Types of Covalent Compounds:

  • Simple Covalent Compounds: e.g., Water (low boiling points due to weak intermolecular forces).

  • Giant Covalent Compounds: e.g., Diamond (high melting points due to strong covalent bonds).

Metallic Bonding

• Occurs between metal atoms.

• Example: Iron (Fe).

  • Iron has 2 electrons in its outer shell.

• Metal atoms share electrons, creating a sea of delocalized electrons throughout the lattice.

• Positive nuclei are held together by the delocalized electrons, creating strong metallic bonds.

• Properties:

  • Strong bonding leads to high melting points.