Ionic bonding + properties

An ionic compounds is an ______ _______ compound. Hence, _______

Electrically neutral. The total positive charge from the positive ions must be equal to the total negative charge from the negative ions.

Ionic bond

The strong electrostatic forces of attraction between oppositely charged ions.

What structure does ionic substances have?

Giant ionic crystal lattice

Giant ionic crystal lattice

The alternating cations and anions forming a 3D structure - a cation and an anion in an ionic compounds will continue to attract other anions and cations

What is lattice?

A regular arrangement of particles which could be atoms, ions or molecules

What are the properties of giant ionic crystal lattices?

• Hard

• Brittle

• Conduct electricity in molten and aqueous states

• Soluble in aqueous solvents but not in organic solvent

• High melting & boiling points

Hardness of giant ionic crystal lattices?

Hard.

Strong electrostatic forces of attraction between oppositely charged ions causes ions to resist motion. Large amount of force is needed to overcome the bonds, hence ionic compounds are resistant to deforming.

Why are giant ionic crystal lattices brittle?

• When a strong enough force is applied, ions move away from their lattice positions and are displaced

• When ions of the same charge approach each other, the strong repulsive forces between these ions cause the lattice structure to cleave cleanly.

Why can giant ionic crystal lattices conduct electricity in molten and aqueous states?

There are mobile ions as:

• (aqueous) the ionic compounds can dissociate in water to form ions

• (molten) large amount of energy can overcome the strong electrostatic forces of attraction between oppositely charged ions

Why are giant ionic crystal lattices unable to conduct electricity in the solid state?

Ions are not mobile as they are held in fixed positions in the ionic lattice by strong electrostatic forces of attraction, hence they cannot move around to carry electrical charges.

Why do giant ionic crystal lattices have high melting & boiling points?

Large amount of energy is required to overcome the strong electrostatic forces of attraction between oppositely charged ions.