Ionic Bonding

Ionic Bond

The strong electrostatic attraction between two oppositely charged ions

What affects the strength of an ionic bond

-Ionic charges

-Ionic radii

How does ionic charge affect the strength of an ionic bond

The greater the charge, the stronger the ionic bond

Explain how the ionic radius affects the strength of an ionic bond

Smaller ions have stronger bonds as electrostatic attraction gets weaker over distance

Explain how ionic radius changes down a group

It increases as extra electron shells are added

Isoelectronic ion

Ions of different atoms with the same number of electrons

Explain the trend of ionic radius, when looking at a set of isoelectronic ions of increasing atomic number

The atomic radius decreases as there are the same number of electrons, but more protons, so the electrons are more attracted to the nucleus, pulling them in

Structure of an ionic compound

Giant lattice

Giant ionic lattice

A cube of repeated, alternating positive and negative ions

Properties of ionic compounds

-High melting point

-Soluble in polar solvents, but not non-polar solvents

-Don’t conduct electricity when solid

-Conduct electricity when molten or aqueous

-Brittle/Can’t be shaped

Why do ionic compounds have high melting points

Ionic bonds are strong

Why do ionic compounds dissolve in polar solvents, but not in non-polar solvents

The ions are charged, so they are pulled apart by polar molecules, but non by non-polar molecules

Why don’t ionic compounds conduct electricity when solid

Ions are not free to move

Why can ionic compounds conduct electricity when molten/aqueous

Ions are free to move

Why are ionic compounds hard to shape

They are brittle- If you try to slide a layer of ions over another, you’d get like charges on top of each other, splitting the compound