Chemistry: Chapter 6 - Chemical Bonding

6.1 The Stable Noble Gas Structure
Atoms of noble gases are usually unreactive or stable.
An atom is stable if it has a duplet or octet configuration.

6.2 Forming Ions
An ion is a charged particle formed from an atom or a group of atoms by the loss or gain of electrons.

Metals form positively charged ions (cations) whereas non-metals form negatively charged ions (anions).

Metals give electrons and non-metals take electrons.

6.3 Ionic Bond : Transferring Electrons
When metals react with non-metals, an ionic compound is formed.

Positive ions and negative ions are attracted to one another by electrostatic attraction.

An ionic bond may also be known as an electrovalent bond.
Compounds that has ionic bonds are called ionic compounds.

Structure of Ionic Compounds
Ionic compounds are arranged in a giant lattice structure or crystal lattice.


Physical Properties of Ionic Compounds

1. Ionic compounds have high melting and high boiling points. (Non-volatile substances)
2. Ionic compounds are soluble in water but not in oil.
3. Ionic compounds do not conduct electricity in the solid state but in the molten state as there are free-moving ions that conduct electricity.

6.4 Covalent Bond: Sharing Electrons
When non-metals react with non-metals, an covalent bond is formed.

Structure of Covalent Bond Compounds



Physical Properties of Covalent Substances

1. Covalent compounds have low melting and low boiling points.
   
2. Covalent compounds are soluble in oil but now in water.
3. Covalent compounds do not conduct electricity in any state.

*Ionic compounds have electrostatic attraction. Covalent compounds have intermolecular forces.