Chemistry Paper 1

contains glass beads, hottest at the bottom

found that the beams of particles were attracted to positive charge - evidence for negative electrons

found that light given out when atoms were heated only had specific amounts of energy - evidence for energy shells where energy is given out when electrons fall to a lower shell

average value that takes account of the abundance of the isotopes of the element

physical eg. density and radioactivity

metal hydroxide + hydrogen

soluble in water, colourless, alkaline

react vigorously to produce metal chlorides (white solids) - dissolve in water to form colourless solutions

layer of oxide forms on surface, alkali metals have to be stored in oil to stop this

burn vigorously and produce white smoke of their oxides

- electrostatic forces of attraction between nucleus and outer shell weaker
- inner shells 'shield' outer electrons from positive charge of nucleus

harder to attract and gain an extra incoming electron

- John Dalton - order of atomic weight
- John Newlands - order of mass, noticed every 8th element seemed similar, didn't take undiscovered into account

decreases down the group

increases down the group

increases down the group

- very low density
- relatively low boiling point

typical of metals
- good conductors
- hard and strong
- high densities
- high BP (apart from mercury)

much less reactive than alkali metals

- has to be heated storngly before
- black coating of copper (ii) oxide forms slowly on surface

- chlorine has to be passed over the iron and heated very strongly inside a horizontal pyrex tube
- reaction forms red iron (iii) chloride

- copper has no reaction
- iron rusts slowly over time

- structural materials in construction industry
- catalysts in chemical industry (nickel in margarine production, iron in Haber process)

blue, due to Cu$2+$ ions

pale green, due to Ni$2+$ ions

dark green, due to Cr$3+$ ions

pale pink, due to Mn$2+$ ions

transition metals can form more than 1 ion

- no forces shown
- all particles represented as solid spheres

- due to many atoms/ions/molecules acting together
- individual atoms don't have the physical properties of the substances that contain them

doesn't show true shape of molecule

doesn't show tetrahedral shape as well as a molecular model kit

- electrons shown in fixed positions between 2 atoms but electrons in covalent bonds are constantly moving
- all electrons are identical so shouldn't be represented as dots and crosses

can conduct when molten/dissolved in water - ions free to move and carry charge

- no free electrons/ions
- no overall charge so can't carry electrical charge

- each carbon atom forms 3 covalent bonds with 3 other atoms, forming layers of hexagonal rings
- no covalent bonds between layers
- one electron from each carbon atom is delocalised

- very high BP
- insouble in water
- (apart from graphite) hard and don't conduct electricity

diamond, graphite, silicon dioxide

single layer of graphite 1 atom thick

- better conductor than graphite
- very low density
- most reactive form of carbon
- pieces of it are incredibly strong for their mass

- more powerful computer chips
- flexible electronic displays

- molecules of carbon atoms with hollow shapes
- based on hexagonal rings of carbon atoms but may also contain rings with 5 or 7 carbon atoms

cylindrical fullerenes with very high length to diameter ratios

- reinforcing composite materials (eg. in tennis rackets) due to high tensile strength
- electronics industry due to high conductivity

- drug delivery
- lubricants (like graphite)
- catalysts due to large SA:V of their nanoparticles

- layers of regular patterns
- electrons in the outer shell of metal ions are delocalised, so free to move throughout whole structure
- sharing delocalised electrons creates strong metallic bonds

have atoms of different sizes, so more difficult for layers to slide over each other

1x10$-9$m

particulate matter - particles in the air such as pollutants, pollen or dust

1-100nm

- 100-2,500nm
- 0.1-2.5μm
-PM$0.1$-PM$2.5$

- 1x10$-5$m
- 10μm
- PM$10$

- exposure of such a large percentage of atoms at the surface of nanoparticles makes them highly reactive
- so smaller quantities are needed

- glass coated with titanium oxide nanoparticles
- sunshine triggers a chemical reaction that breaks down dirt that lands on the window
- when it rains, water spreads evenly over the glass, washing off the broken down dirt

nanoparticles are coated in silica - more effective at blocking the sun's rays than conventional UV absorbers

absorbed deeper into the skin

- tumours have thin, leaky blood vessels with holes large enough for the gold nanoparticles to pass into
- nanoparticles can't get into healthy blood vessels
- laser directed at the tumour, transferring energy to and warming up gold nanoparticles
- temperature of tunour increases enough to change the properties of its proteins but barley warms the surrounding tissue

continuously release a low level of silver ions to protect against bacteria

could be used to construct incredibly small electronic circuits - make computers with vastly improved memory capacitities and speeds

can detect tiny traces of a gas present in the breath of asthmatics before an attack

- nanoparticle large SA:V makes them very reactive
- if a spark is made by accident near a large quanitity of the catalyst, there could be a violent explosion

- could have unpredictable effects on cells
- nanoparticles in the environment could affect aquatic life by accumulating in organisms over time

6.02 X 10$^23$ - number of atoms, molecules or ions in a mole of any substance

$mol =\frac{m}{Mr}$

$Percentage yield =\frac{mass of product made}{maximum theoretical mass}\times 100$

- reaction may be reversible
- some reactants may react to give unexpected / unwanted products in alternative reactions
- some product may be lost in handling / left in apparatus
- reactants may not be pure
- some desired product may be lost during separation from reaction mixture

$atomeconomy=\frac{Mr (of desired product)}{Mr(of all reactants)}\times 100$

$Concentration=\frac{mass of solute (g)}{voume of solution (dm^3)}$

$1000cm^3$

- used to find out how much acid is needed to completely react with an alkali
- point at which they have reacted completely = end point

one mole of any gas at room temperature (20*C) and room pressure (1 atmosphere pressure) = 24dm$^3$

$Volume of gas (dm^3) = Number of moles of gas \times 24dm^3$

metal oxides

don't change in a reaction - aren't shown in ionic equations

REDOX

by reduction if the metal is less reactive than carbon