Bonding structure and properties of matter Flashcards
group 1 and 2 elements are most likley to form ions
- metals
- lose electrons
- form positive ions
- cations
group 6 and 7 are most likely to form ions
- non-metals
- gain electrons
- form negative ions
- anions
describe the ionic compound’s structure: the giant ionic lattice
- ions form closely packed regular lattice arrangement
- strong electrostatic forces of attraction
- between oppositely charged ions
- in all directions of lattice
ionic compounds all have similiar properties
- high melting/boiling points
- solid: can’t conduct electricity
- soluble
why do ionic compounds have high melting/boiling points?
- many strong bonds between ions
- lots of energy needed to overcome
why do solid ionic compounds not conduct electricity?
- ions held in place
- melted: ions free to move carry current
what happens when ionic compounds dissolve in water?
- ions seperate
- free to move
- carry electric current
what are simple molecular substances?
- made up of molecules containing few atoms
- joined by covalent bonds
what are the properties of the simple molecular substances?
- atoms within molecules very strong covalent bonds
- low melting/boiling points
- gases/liquid at room temp
- don’t conduct electricity
although simple molecular structures have very strong covalent bonds…
the forces of attraction between these molecules are very weak
why do simple molecular structures have low melting/boiling points?
- only need to break feeble intermolecular forces
- molecules easily parted
what happens when a molecular substance gets bigger?
- strength intermolecular forces increase
- more energy to break
- melting/boiling point increase
why do molecular compounds not conduct electricity?
- aren’t charged
- no free electrons/ions
what are polymers?
- long chains
- repeating small units
atoms in a polymer are joined by…
strong covalent bonds
why are polymers solid at room temp?
- intermolecular forces between molecules larger
- more energy needed to break them
why do polymers have low boiling points?
- intermolecular forces weaker than ionic or covalent bonds
- lower boiling point than ionic or giant molecular compounds
what are macromolecules?
- giant ocvalent structure
- atom strongly covalent bond
- very high melting/boiling point
- don’t conduct electricity: no charged particles
describe the macromolecule of diamond
- each carbon atom forms 4 covalent bonds
- very rigid giant covalent structure
decribe the macromolecule of graphite
- each carbon atom forms 3 covalent bonds
- create hexagon layers
- each carbon atom has one delocalised electron
decribe the macromolecule of silicon dioxide
- sand made of silica
- each grain one giant structure of silicon and oxygen
what are the properties of a diamond?
- giant covalent structure makes it really hard
- very high melting point: strong covalent bonds lots energy to break
- doesn’t conduct electricity: no free electrons/ions
how does graphite containing sheets of hexagons make it ideal as lubricating material?
- soft and slippery
- no covalent bonds between layers
- held weakly, free to move over eachother
why does graphite have a high melting point?
- lots energy to break
- covalent bonds in layer
why can graphite conduct electricity and thermal energy?
- 3/4 outer electrons used in bonds
- one free electron can move
what is graphene?
- sheet of carbon atoms joined in hexagons
- one atom thick
- two-dimensional compound
what are the properties of graphene?
- strong: network of covalent bonds
- light: add to composite materials improve strength without added weight
- conduct electricity through whole structure
what are fullerenes?
- molecules of carbon
- shaped close tubes/hollow balls
how are carbon atoms arranged in fullerenes?
- mainly hexagons
- pentagons
- heptagons
how can fullerenes be used to deliver a drug into the body?
-structure cages other molecules
why can fullerenes make great industrial catalysts?
-large surface area
what is the buckminsterfullerene?
- first discovered
- molecular formula C60
- hollow sphere
what is metalic bonding?
- delocalised electrons in outer shell of metal atom
- strong froces of electrostatic attraction
- between positive metal ions and shared negative electrons
why are most metals solid at room temp?
- strong electrostatic forces of attraction
- lots energy to break
- very high melting/boiling point
why are most metals malleable?
-layers of atoms slide over eachother
what are alloys?
- mixture of two or more metals
- different sized atoms
- distorted layers
- pure metals too soft
how are alloys harder than pure metals?
- different element shave different sized atoms
- new metal atoms ditort layers of metal atoms
- more difficult to slide over eachother
the state of something at a certain temp depends on…
how strong forces of attraction are between particles of material
how strong froces of attraction are depends on…
- material
- temp
- pressure
explain the particle theory of a solid
- strong forces of attraction between particles, holds close together in fixed position to from lattice arangement
- definite shape and volume
- vibrate about their positions
explain the particle theory of a liquid
- weak forces of attraction between particles, randomly arranged, move past eachother, stick together
- definite volume, don’t keep definite shape
- constantly move in random motion
explain the particle theory of a gas
- very weak forces of attraction, free to move, far apart
- don’t keep definite shape or volume
- move constantly in random motion
solid melted to liquid
- particles gain more energy
- vibrate more: weakens forces
- melting point: enough energy to break free
liquid boiled to gas
- particles gain more energy
- more faster: weakens and breaks bonds
- boiling point: enough energy to break bonds
gas condensed to liquid
- cools: particles no longer have enough energy overcome forces
- bonds form
- boiling point: many bonds form gas to liquid
liquid freezed to solid
- cools: particles have less energy
- not enough energy to overcome forces: more bonds form
- melting point: so many bonds form liquid to solid
what are coarse particles (PM10)?
- dust
- diameter: 2.5x10-6m and 1x10-5m
what are fine particles (PM2.5)?
-diameter: 1x10-7m and 2.5x10-6m
how can you calculate the surface area to volume ratio?
surface area/volume
how is electricity conducted in a metal?
- giant ionic lattice
- made up of positive ions
- with free electrons
- moves to carry charge
why is alloys used in dental braces?
-turn back into original shape
why are instrumental methods used to detect impurities on metals?
- accurate
- small samples
