Ionic Bonding

Ionic Compounds

Compounds (consisting of two or more elements) of ions (cations and anions).

Alternative name for ionic compounds in Chem

Salt

Structure of Ionic Bond

3D Lattice

What does the 3D Ionic bonding lattice result in?

Alternating arrangement of cations and anions

Ionic bonding

The attraction (or electrostatic forces) between cations and anions in the ionic lattice.

Hardness & High melting point

There are strong attractions between the cations and the anions due to the alternating arrangement. These attractions require a lot of energy to break.

Brittleness

When a strong force is applied, the layers of ions will move, so ions of like charge are shifted so they are next to each other. The resulting repulsion between similarly charged ions causes the crystal to shatter.

Metals conduct electricity due to the presence of delocalised electrons

In general, a material will conduct electricity if there are free-moving charged particles present in the material. These particles can be electrons (negatively charged) or ions.

Does not conduct electricity in the solid state

In the ionic solid, the cations and anions are held rigidly in place, and cannot move throughout the solid. Though the material has charged particles in the form of ions, they are not free-moving. This prevents the material from conducting electricity.

Conduct electricity in the molten and aqueous state

The ions can be ‘free’ and become free-moving by either melting the lattice (creating molten ionic compounds) or by dissolving the ionic compounds in water (provided that the compound is soluble in water).

Octet Rule

The octet rule is a simple way to predict the charge of an ion of an element. The octet rule reasons that atoms would gain or lose electrons in order to achieve a full outer shell of 8 electrons. The octet rule only applies to main group elements. For the transition metals, the charges of the ions may vary and there is no simple way to predict it.