bonding, structure and properties of matter Flashcards
what is ionic bonding
- when a metal and non-metal form a compound
- a metal will give a non-metal it’s excess electrons
how are the elements in an ionic compound held together
electrostatic forces
what is the structure of an ionic compound
regular lattice structure
what are the properties of ionic compounds
- high melting and boiling points due to many strong ionic bonds
- can conduct electricity when in liquid form
what is covalent bonding
- when two non-metals share electrons
- they both need more electrons for a full outer shell so they have to share
what are the disadvantages of a displayed formula
- doesn’t show the relative size
- doesn’t show the shape and arrangement
what are the type of substances covalent bonds can make
- simple molecular substances eg. H2O, Cl2
- polymers
- giant covalent structures eg. diamond and graphite
describe the strength of the bonds that hold simple molecular structures together
- a simple molecule has multiple atoms covalently bonded together, these covalent bonds between atoms are very strong
- however the forces of attraction between separate molecules are weak
why do simple molecular substances have low melting and boiling points
only the weak forces of attraction that hold the separate molecules together need to be broken which requires little energy
what is the general structure of giant covalent structures like
regular repeating lattice
what is an allotrope
different structural forms of the same element in the same physical state
what is the maximum number of bonds carbon can make
4
what are the properties of diamond
- very strong due to all the covalent bonds
- high melting and boiling points
- cannot conduct electricity
what are the properties of graphite
- layers of flat hexagonal sheets
- soft as the layers are held together weakly
- can conduct electricity as each carbon atom has 1 free electron (delocalised)
- high melting and boiling point
what is graphene
a single layer of graphite
what are fullerenes
tiny tubes and spheres made from graphene
what are fullerenes used for
- formed around drugs to deliver them into the body
- large surface area to volume ratio so they can be used as industrial catalysts
- nanotechnology as they can conduct electricity
- strength other materials
what is a buckminsterfullerene
one of the first fullerenes made, hollow sphere made of 60 carbon atoms
what is metallic bonding
the type of bonding you get between metal ions
what is the structure of metallic bonding
- metal ions arranged in a regular pattern
- outer shell electrons are delocalised
- strong electrostatic attraction between positive ions and negative electrons
what are the properties of metallic bonding
- can carry electric current and thermal energy
- malleable (pure metals)
what is an alloy
mixing together 2 or more different metals
why do we use alloys
disturbing the regular structure with different sized atoms makes them harder than pure metals
what is wrong with the particle model
- particles are solid, inelastic or spheres
- doesn’t include details like how many or how strong the forces are
