Ions

• Charged particles formed when atoms gain/lose electrons.
• Metal atoms lose electrons → positive ions (cations).
• Non-metal atoms gain electrons → negative ions (anions).
• Examples: Na, Cl.

Ionic Bonding

• Electrostatic attraction between oppositely charged ions.
• Occurs between metals and non-metals.
• Forms giant ionic lattices.
• Characterized by high melting and boiling points.
• Conduct electricity when molten or dissolved in water.

Covalent Bonding

• Involves sharing of electrons.
• Occurs between non-metals.
• Forms simple molecules or giant covalent structures.
• Usually has low melting and boiling points (for simple molecules).
• Do not conduct electricity (exception: graphite).