10Formation of Ionic Bonds Na+Cl-Properties of Ionic CompoundsIn an ionic compound the positive and negative parts are arranged so minimize repulsion. This arrangement is called a crystal lattice.
11Properties of Ionic Compounds Hard brittle solidsHigh boiling points_________ melting points_________conductors of heat and/or electricityThese properties are all related to the crystal lattice and strength of bond
12Properties of Ionic Compounds Melting and boiling pointRecall that the solids are rigidly arranged, liquids more loosely arranged, and gases most loosely arranged. (picture on next slide)
14Properties of Ionic Compounds Also recall melting point is the temperature that a solid becomes a liquid and boiling point is the temperature that a liquid becomes a gas.So for particles to get further away from each other (solid to liquid or liquid to gas) enough energy (temperature) must be supplied to break (or loosen) the strong ionic bonds between particles.
15Properties of Ionic Compounds Ionic compounds are hard brittle solidsRecall the picture of the crystal lattice. What if you moved one of the columns?
17Properties of Ionic Compounds You notice in the second picture that positives and negative line up rather than alternate.Since we know positives repel each other and negatives repel each other the second picture will split down the middle because of the positive-positive and negative-negative repulsion.
18Properties of Ionic Compounds In the solid state ionic compounds are nonconductors. However, in a liquid state or dissolved in water they are good conductors.An ionic compound dissolved in water is called an electrolyte.It’s the electrolytes in water that make it a good conductor of electricity. If you have pure water it does not conduct electricity.
19Properties of Ionic Compounds Energy and the ionic bondLattice energy is the energy required to separate one mole of the ions of an ionic compound.Lattice energy is a reflection of strength of the forces holding ions place.The more negative the lattice energy the stronger the attraction.