Bonding + Structure Pt2 Flashcards
Define ionic bonding
The strong electrostatic attraction between oppositely charged ions
How does ionic radius effect the melting point of an ion
- smaller ions have smaller ionic radii
- greater electrostatic attraction
- ions smaller and closely packed
- increasing melting point
How does ionic charge effect the melting point of an ion
- greater charge = stronger ionic bond
- have a higher charge density
- increase melting point
How does ionic radius change down a group and why
It increases
- all have the same charge however number of electron shells increases
What are isoelectronic ions
Ions with the same number of electrons
From N3- to O2- how does ionic radius change and why
- ionic radius decreases
- all have the same number of electrons so equal number of electron shells
- number of protons increase so greater nuclear charge
- decreasing ionic radius
What type of structure do ionic compounds form
Giant ionic lattices
Physical properties of ionic compounds
- high melting point
- soluble in water but not non-polar solvents
- doesn’t conduct electricity when solid but does when molten or dissolved
- brittle, cannot be shaped
What does high melting point in ions explain
- ions held together by a strong attraction
- fits ion model as positive and negative ions strongly attracted
What does being soluble in water but not non-polar solvents show
- particles charged
- ions pulled apart by polar molecules like water but not by non-polar molecules
What does not conducting electricity when solid but when molten or dissolved show
- supports idea of ions present in fixed position by strong ionic bonds when solid but free to move (and carry a charge) when liquid or in solution
What property supports Lattice model and why
- ionic compounds are brittle
- putting layers of the compound over each other will cause repulsion between the two equally charged ions
- very strong repulsion so will break
