bonding, structure, properties of matter Flashcards
what are ionic bonds
two ions (metal and non metal) have opposite charges and therefore are attracted to each other by electrostatic forces. these created ionic compounds
- the transfer of electrons
what is the structure of an ionic compound and how are these presented
3D lattice structure because each ion is attracted to all those around it
ball and stick diagrams
what are the properties of ionic compounds
high melting and boiling points
conductors of electricity
why are high melting and boiling points required for breaking ionic compounds
high melting and boiling points - determined by the strength of the bonds. because there is loads of ionic bonds, a lot of energy is required to break these. therefore needing a high temperature
what form do ionic compounds need to be in, in order to conduct electricity and why
conducts electricity when melted or disolved in water
when in solid form, all particles are fixed and therefore when melted or in liquid, ions are free to move. this movement of charged particles conduct electricity
what is the formular for the ionic compounds:
- hydroxide ions
- sulphate ions
- nitrate ions
- carbonate ions
- aluminium ions
hydroxide ions = OH-
sulphate = SO-2
nitrate = NO3-
carbonate = CO3 -2
aluminium = NH4 +
what are covalent bonds
- sharing of electrons between non metals
when both metals are missing electrons and therefore create a bond to share meaning they both have a full outer shell
what diagrams do you use for covalent bonds
dot and cross OR displayed formular. for a displayed formular you place a line where there was a covalent bond
what type of substances do covalent bonds make
- simple molecular substances such as chlorine
-methane, water - larger structures such as polymers and giant covalent structures
what is metallic bonding
bonding between metals
- giant structure of metal atoms are arranged in a regular pattern. they share their outer shell of electrons meaning they become positive ions. there will be strong electrostatic attractions meaning metals are held together making it strong
what are properties of metallic bonding
- very strong
- high melting and boiling point
- good conductors of electricity and heat because of delocalised electrons
- malleable because of the regular structure, layers slide over each other
what are delocalised electrons
Bonding electrons that are no longer associated with any particular atom. electrons that are free to move
what are alloys
metallic bonds that contain two or more different elements. two different metals or non metals with different sized atoms
why do the two different elements need different sized atoms
disrupts the regular structure and layers can no longer slide over each other making them much harder than pure metal.
what is an example of an alloy and where is it used
steel, this is used in cars/ planes
what are the three states of mater and explain the properties and how they change between states
solid - strong forces of attraction meaning the particles are held together. this means there is a definite shape or volume
liquid - adding heat to solid meaning particles gain more energy causing them to vibrate breaking the bonds. weak forces of attraction meaning the particles are free to move
gas - more heat added, particles gain more energy weakening force holding particles. once at boiling point, particles will be able to break bonds all together. liquid evaporates to gas.
what are the positives and negatives of the particle model
negatives - particles aren’t actually solid, inelastic or sphered shape
- doesn’t include details of the forces between particles such as how strong
positives - it is a useful simplification to allow understanding of the complicated concept
what are state symbols for each state of matter
solid (s), liquid (l), gas (g), aqueous (aq) - disolved in water
how can you predict what state something is when given an exam question with information
use an increasing temperature timeline
what are polymers
chain of molecules, each polymer molecules is made up of smaller units called monomers
how do you know that a molecule is a polymer
identify the repeating monomer
use the monomer polypropene and identify the repeating monomer
H CH3 H CH3 H CH3 H
| | | | | | |
H - c - c - c - c - c - c - c - H
| | | | | | |
H H H H H H H
H CH3
| |
(- C - C -) n
| |
H H
describe a polymers melting and boiling point
polymers intermolecular forces are quite weak ( weaker than covenant and iconic) yet because polymers have a large surface area, melting and boiling points a pretty high
what are simple molecular substances
small molecules made up of a few covalently bonded atoms with weak intermolecular forces
what is an example of a simple molecular force
ammonia/ chlorine
why do simple molecular forces only need low temperatures for a melting and boiling point
only low temperatures are needed to break simple molecule forces because they only are breaking intermolecular forces and not covalent bonds
what happens when you decrease down a group of simple molecular forces
the boiling point increases because molecules get larger and therefore increase the amount of intermolecular forces between them.
what is another property of simple molecular forces
not a conductor of electricity
- this is because there are no free electrons and molecules have no electrical charge
what is a giant covalent structure
huge numbers of non metals bonded together by covalent bonds. structured in a regular repeating lattice
what are the properties of a giant covalent structure
- they are very strong
- have very high melting and boiling points
- don’t conduct electricity
what is an allotrope
different forms of the same element in the same physical state
what are two allotropes of carbon and what are their structures
diamond and graphite
- giant covalent structures
what are the properties of diamond and why
- very strong
- high melting point because they are covalently bonded
- doesn’t conduct electricity because the carbon atoms are bonded to four other carbon atoms meaning there are delocalised electrons
what are the structure and properties of graphite and why
atoms are arranged into hexagons which are arranged into flat sheets on top of each other to form layers
- soft because the layers are held together weakly with no covalent bonds
- high melting point because the INDIVIDUAL LAYERS have covalent bonds
- conduct electricity because there are only three electrons and therefore electron gets delocalised
what is a single layer of graphite called
graphene
how is a fullerene formed
layers of graphite (graphene) is taken from the ground and turned into tubes and spheres
what are the uses of fullerenes
- used to surround drugs because they can be formed around other molecules
- because of the large surface area: volume they can be used as an industrial catalyst
- nanotubes can be used to make nanotechnology because they can conduct electricity
- silver nanoparticles can kill bacteria in things like plasters because of their antibacterial properties
what are some issues of nanoparticles give an example
because they are relatively new the effect on our bodies isn’t fully understood
an example would be sun cream
- it is more effective at protecting our skin yet we don’t know if it is getting into our skin and harming our cells
- also don’t know if it is harming our environment and what happens when they are washed into the sea
