2.12 - Ionic Bonding Flashcards
What is ionic bonding confined to?
Solid materials
What is ionic bonding?
The regular array of oppositely charged ions extending through a giant lattice network
What exists between the ions?
Electrostatic forces of attraction
Are these strong or weak?
Strong
How does the strength of a small ionic compound compare to that of a larger one?
The strength increases significantly with a decrease in either the anion or cation size
What does the size of the ions determine about the lattice structure?
How closely the ions are packed together
What happens if the charges on each ion are increased?
The strength of the ionic bond increases
Why are ionic radii hard to measure?
Because the environment of the ion can change the ionic radius, and each method of measuring the ionic radius will give a slightly different value
What is the trend in ionic radius down a group?
It increases
Why?
Because the number of orbitals increases, so the ion takes up more room
What is the trend in ionic radius across a period?
It decreases
Why?
Because the electronic configuration of the ion does not change, but the nuclear charge is increasing, so the electrons are attracted more strongly, and thus pulled closer to the nucleus
What are the 4 main physical properties of ionic compounds?
- High melting temperatures
- Brittleness
- Poor electrical conductivity when solid, but good when molten
- Often soluble in water
Why do ionic solids have high melting temperatures?
The giant lattice network has lots of electrostatic forces of attraction, which have to be overcome, and this requires a lot of energy
Why are ionic solids brittle?
Because the layers of the ionic solid can slide over each other, causing the ions to repel one another, and the solid to break apart
