Summer assessment 2 Flashcards
what are ions?
charged particles
What is ionic bonding between?
a metal and non-metal
What is ionic bonding?
oppositely charged ions are strongly attracted to one another by electrostatic attrations
What does ionic bonding form?
giant ionic structure
Describe giant ionic structure?
- ions held together by closely packed 3D lattice arrangement
- strong electrostatic attraction
- high melt + boiling point
- not electrical conductors when solid, only when dissolve in water or melt them
Definition of covalent bond?
strong electrostatic attraction between negatively charged shared electrons and the positively changed nuclei of the atoms involved
Describe simple molecular structures?
- very strong covalent bond
- weak intermolecular forces of attraction between molecules
- low melting and boiling point
Describe giant covalent structures?
- strong covalent bond
- high melting and boiling
- dont conduct electricity
- insoluble in water
Describe diamond?
- network of carbon atoms with four covalent bonds
- strong covalent bonds
- high melting point
- hard rigid lattice structure
- doesnt conduct
Describe graphite?
- each carbon forms three covalent bonds
- layers of carbon atoms with weak intermolecular forces which can slide over each other making it slippery and soft
- high melt and boil
- one delocalised electron and can conduct electricity
Describe C60 fullerene?
- hollow sphere with 60 carbon atoms
- intermolecular foces which can slide over each other - soft
- one delcocalised but cant move molecules so poor conductor
What is the name of group 7?
halogens
What happens as atomic number increases for halogens?
elements have darker colour and a higher boiling point
Describe chlorine?
poisonous green gas
Describe bromine?
red-brown liquid gives off orange vapour at room temperature
Describe iodine?
dark grey crystalline solid which gives off purple vapour when heated
When do salts form?
when acids react with bases in a neutralisation reaction
acid + base = ?
salt + water