Ionic Compounds (page 114) Flashcards
Ionic compounds have a structure called what?
Giant Ionic Lattice
Explain what Giant Ionic Lattice is?
It is where Ions form a closely packed regular lattice arrangement and there are very strong electrostatic forces of attraction between oppositely charged ions in all directions of the lattice.
Why is a single crystal of sodium chloride (table salt) one giant ionic lattice?
The Na+ and Cl- ions are held together in a regular lattice. the lattice can be represented in different ways
See diagram, page 114 (very important to learn the structure of what sodium chloride looks like)
The model shows (page 114) the relative sizes of the ions, as well as the regular pattern of an ionic crystal, but it only lets you see the outer layer of the compound
Also diagram on page 114 shows…
The Ball and Stick model.
what do the ball and stick model show you on page 114 diagram?
It shows you the regular patterns of an ionic crystal, and shows how all the ions are arranged. it also suggests how the crystal extends beyond what is shown in the diagram.
What similar properties do Ionic compounds have?
They all have high melting points and high boiling points due to the many strong bonds between the ions. It takes lots of energy to overcome this atraction.
when they’re solid, the ions are held in place, so the compounds can’t conduct electricity. when ionic compounds melt, the ions are free to move and they’ll carry electric charge.
some ionic compounds dissolve in water. the ions separate and are all free to move in the solution, so they’ll carry electric charge
Explain what the empirical formla of an ionic compound means?
The empirical formula of a compound isthe simplest whole number ratio of atoms of each element in the compound.
How would you work out the empirical formula of a compound if it is a dot and cross diagram?
if a dot and cross diagram is used, you count up how many atoms there are of each element. you write this down to give you the empirical formula.
how would you work out the empirical formula if you are given a 3D diagram of the ionic lattice?
work out what ions are in the ionic compound.
then balance the charges of the ions so that the overall charge on the compound is zero
see diagram on page 114 for example
