C3 Flashcards
Ionic bonds
Strong electrostatic forces of attraction between oppositely charged ions.
When can ionic compounds conduct electricity?
When they are molten or dissolved in water, because that makes the ions mobile.
Covalent bonds
Formed when atoms of non-metals share pairs of electrons with eachother. Each shared pair of electrons is a bond. Many of these substances will have giant covalent structures.
Simple molecules
Have low melt/boiling points because of weak intermolecular forces (but do have strong bonds between atoms). Have no overall charge, so can’t conduct electricity.
Diamond structure
Each carbon atom has four covalent bonds meaning all electrons are being used so diamond can’t conduct electricty. Very strong structure
Graphite structure
Aranged in layers with no bonds between layers making graphite slippery. Can conduct electricity as delocalised electrons can move between it’s layers.
Allotropes
Substances made from the same element but with different intermolecular structures.
Fullerenes
Cage-like structures and tubes (made from carbon atoms) based on hexagonal rings of carbon atoms. Used to transport drugs around the body and in sports equipment.
Graphene
A single layer of Graphite which is just one atom thick. Is incredibly strong in relation to it’s mass, flexible and a good conductor of heat and electricity.
Bonding in metals
Positively charged metal ions are held together by electrons from the outermost shell of each metal atom. The delocalised electrons move throughout the giant lattice.
Alloy
A mixture of two of more elements, at least one of which being a metal. Harder than pure metals because the regular layers of the pure metal are disturbed by the other element.
Properties of metals
Can be bent and shaped because layers of atoms can slide over eachother. Delocalised electrons allow heat and electricity to be transfered.
