5.2 Ionic bonding and structure Flashcards
(12 cards)
What is the name for the forces between ions in an ionic lattice?
Ionic bonds/ electrostatic forces
How does an ionic lattice form?
Outer shell electron is lost from the metal atom to the outer shell of a non-metal atom
What type of diagram is used to represent the transfer of electrons
Dot and cross diagram
Give 2 features of ionic lattices
Form giant lattice structures
Formed of alternating charges
Properties of ionic lattices:
High melting/boiling point
Soluble in polar solvents
Electrical conductors when molten/in solution
High melting point factors
All solid at room temp
Strong electrostatic forces require a lot of energy to over come
Which factors cause the strength of ionic bonds to increase/decrease?
The higher the charge, the higher the strength of ionic bonds (more electrons have been transferred)
The smaller the ion, the stronger the ionic bond (ions are closer together so bonds are stronger) - if a larger ion is bonded to a much smaller one
Solubility of ionic compounds
Dissolve in polar solvents e.g. water
Polar water molecules break down the lattice due to opposing charges
What happens to an ionic lattice in a polar solvent?
Ionic lattice must be broken down
Water molecules must attract and surround the ions
Factors that affect solubility of ions in polar solvents:
Depends on relative strengths between ions + water molecules
The larger the ionic charge, the lower the solubility USUALLY
Electrical conductivity of ionic compounds:
In the solid state, an ionic compound doesn’t conduct
Only conducts when in solution or when molten
Why can’t ionic compounds conduct when solid but can when in solution/molten?
When solid= delocalized electrons aren’t free to move, in a fixed position in ionic lattice
When in solution/molten = delocalized electrons are free to move as solid ionic lattice breaks down
