Ions and Ionic Bonds

Introduction

Atoms can gain or lose electrons to achieve a stable electron configuration. When atoms gain or lose electrons, they become charged particles called ions. The electrostatic forces between these oppositely charged ions form ionic bonds.

Ions

Ions are atoms or molecules that have gained or lost electrons, resulting in a net electrical charge.

Cations: Positively charged ions. Formed when an atom loses one or more electrons.

Anions: Negatively charged ions. Formed when an atom gains one or more electrons.

Ionic Bonds

An ionic bond is a chemical bond formed through the electrostatic attraction between oppositely charged ions.

This attraction is a strong electrostatic force, which is responsible for the high melting and boiling points of ionic compounds.

Formation of Ionic Bonds

1. A metal atom (typically losing electrons) transfers one or more electrons to a non-metal atom (typically gaining electrons).
2. This transfer results in the formation of a positive ion (cation) and a negative ion (anion).
3. The electrostatic attraction between the cation and anion holds them together in a crystal lattice structure.

Properties of Ionic Compounds

• High melting and boiling points
• Brittle (tend to shatter when struck)
• Conduct electricity when molten or dissolved in water (due to the mobile ions)
• Often soluble in water

Representation of Ionic Bonds

Ionic bonds are typically represented in chemical formulas. For example, sodium chloride (NaCl) shows a sodium cation (Na⁺) and a chloride anion (Cl^-).

Ion	Charge	Example
Sodium Ion	$Na^+$	Sodium Chloride (NaCl)
Chloride Ion	$Cl^-$	Sodium Chloride (NaCl)
Calcium Ion	$Ca^{2+}$	Calcium Oxide (CaO)
Oxide Ion	$O^{2-}$	Calcium Oxide (CaO)

Key Takeaway

An ionic bond is a strong electrostatic attraction between opposite-charged ions. This attraction is fundamental to the properties of ionic compounds.