Ionic Bonds | Chemistry for Grade 11 (IGCSE) PDF Download

The Formation of Ions

Ionic Bonding

• An ion is formed when an atom undergoes a process of gaining or losing electrons, resulting in an electrical charge.
• Atoms adjust their electron count to achieve stability, typically by acquiring a full outer electron shell, a configuration that enhances stability.
• This adjustment ensures that the electron arrangement of the ion mirrors that of noble gases such as helium or neon.

Ionisation of Metals and Non-metals

• Metals: All metals can lose electrons to other atoms to become positively charged ions, known as cations.
• Non-metals: All non-metals can gain electrons from other atoms to become negatively charged ions, known as anions.

What is Ionic Bonding?

Ionic Bonding Definition

• Ionic bonding occurs when metal atoms interact with non-metal atoms, resulting in the formation of ionic compounds.
• Metal atoms undergo electron loss, which is then gained by non-metal atoms to create positively and negatively charged ions.
• The attraction between these oppositely charged ions forms a strong ionic bond that holds the compound together.

Ionic Bonding Examples

• Dot-and-cross diagrams are visual tools representing the electron arrangements in ionic or covalent compounds.
• These diagrams use dots and crosses to depict outer-shell electrons, with brackets indicating evenly spread charges and ion charges noted in the top right corner.

Dot and Cross Diagrams

• Electrons in dot and cross diagrams are represented as dots and crosses.
• In a dot and cross diagram:
  • Only the outer electrons are depicted.
  • The charge of the ion is evenly distributed, shown using brackets.
  • The charge on each ion is indicated at the top right-hand corner.
• Only the outer electrons are typically shown.
• The charge of the ion is evenly spread, demonstrated by brackets.
• The charge on each ion is written at the top right-hand corner.

Ionic Bonds between Group I & Group VII Elements

Ionic bonding occurs between elements from Group I and Group VII, such as Sodium and Chlorine forming Sodium Chloride (NaCl).

Process of Ionic Bond Formation

• Sodium, as a Group I metal, loses one outer electron to achieve a full outer electron shell.
• This loss leads to the formation of a positively charged sodium ion with a charge of +1.
• Chlorine, being a Group VII non-metal, gains an electron to complete its outer electron shell.
• The gained electron transforms Chlorine into a negatively charged chloride ion with a charge of -1.
• The resulting oppositely charged ions are then attracted to each other by strong electrostatic forces.

Characteristics of Ionic Compounds

• Ionic compounds exhibit no overall charge due to the balance of positive and negative charges.
• They are held together by strong ionic bonds formed from the attraction between ions of opposite charges.

In summary, Ionic bonding involves the transfer of electrons between Group I and Group VII elements, leading to the formation of stable ionic compounds like Sodium Chloride.

Formula of Ionic Compound

• The formula of an ionic compound like sodium chloride (NaCl) represents the ratio of the ions present in the compound.