ocr gateway gcse chemistry

atomic number

the number of protons in the nucleus of an atom

relative atomic mass

the number of protons and neutrons in the nucleus of an atom

john dalton

who discovered the solid atom model, identifying that each element contained a different type of atom

jj thomson

who discovered the electron and the idea of the plum pudding model

earnest rutherford

who discovered the nucleus and the planetary model by alpha particles through gold foil

neils bohr

who discovered that electrons occupy fixed energy levels around the nucleus

10 -23

the mass of an average atom in grams

10 -10

the radius of an average atom in metres

cation

what is a positively charged ion called

anion

what is a negatively charged ion called

empirical

which formula shows the simplest whole number ratio of atoms in a compound

pure

what time of compounds have a definite single melting and boiling point

filtration

which method separates an insoluble solid from a liquid

crystallisation

which method separate a solvent from a dissolved solid

powder

what will you get instead of crystals if you heat too strongly during crystallisation

solute

what is the substance that is dissolved in a solution

solvent

what is the liquid that something gets dissolved into

distillation

what method separates a solvent from a solute in a solution

chromatography

what method separates mixtures

mobile

which phase moves in chromatography

stationary

which phase doesn't move in chromatography

silica

what is the stationary phase in thin layer chromatography and gas chromatography

solvent

what is the mobile phase in thin layer chromatography

analysis

what is easier after tlc than paper chromatography

carrier gas

the mobile phase in gas chromatography

retention time

amount of time a compound spends in stationary phase in gas chromatography

mendeleev

who arranged the elements according to atomic mass and used the arrangement to predict the properties of missing elements

ionic compounds

what are charged particles that are soluble in water

ionic

what is the bond between a metal and a non-metal

covalent

what is the bond between two non-metal atoms sharing a pair of electrons

electrostatic

what type of attraction forms between nuclei and shared electrons in a covalent bond

intermolecular

what force is weak between molecules and makes simple covalent molecules have low melting and boiling points

diamond

what is the allotrope of carbon that bonds to four other carbons, is a giant covalent structure and requires a lot of energy to break

graphite

what is the allotrope of carbon that bonds to three other carbons, is arranged in flat slidy sheets, and can conduct electricity

electrons

which free moving particles allow graphite to conduct electricity

ions

which free moving particles allow dissolved ionic compounds to conduct electricity

graphene

what is the allotrope of carbon that is a one atom thick layer of graphene, which is strong and conducts electricity

fullerenes

what carbon allotropes are shaped like balls or tubes

buckminster

what type of fullerene is spherical, sued for drug delivery systems and lubricants

c60

what is the formula of a buckminsterfullerene

nanotube

what is a strong and lightweight fullerene used in reinforcing structures and sporting equipment

monomers

what joins together in polymerisation

intermolcular forces

what gets stronger the longer a molecule is, making polymers have higher melting and boiling points than monomers

crystalline

what type of structure is made when a polymer has no side branches and the molecules are lined up neatly

crosslinks

what can be added between polymer molecules to make them tougher

thermosoftening

what type of polymer has its chains in a tangled web which is easy to seperate

thermosetting

which type of polymer has its chains cross linked by strong covalent bonds

metallic

which strong bonds allow metals to have high melting and boiling points

electrostatic

what type of attraction holds delocalised electrons ad positive metal ions together in metallic bonding

electrons

which particles are left to move freely in metallic bonding

1-100

what is the radius of nanoparticles in nanometres

10 -9

how big is a nanometre in metres

more

are nanoparticles more or less reactive

displacement

what type of reaction happens when a more reactive element takes the place of a less reactive element

6.02 x 10 23

what is the value of the mole

mass / mr

the amount of a substance in moles =

g/mol

what is the unit for molar mass (or mr)

exothermic

which type of reaction releases heat, and has an overall negative energy change

endothermic

which type of reaction absorbs heat, and has an overall positive energy change

acid

what substance dissolves in water to from H+ ions

base

what substance will neutralise an acid to produce a salt and water

alkali

what substance dissolves in water to produce OH- ions

hydrogen

what is produced with a salt when an acid and a metal react

water

what is produced with a salt when an acid and a metal hydroxide react

water

what is produced with a salt when an acid and metal oxide react

water and co2

what is produced with a salt when an acid and metal carbonate react

metal

where does the first half of the salt name come from

acid

where does the second half of the salt name come from

strong

which type of acids are fully ionised

10 -ph

how do you find the concentration of H+ ions in a substance in moles per litre based on ph

cathode

which electrode is negatively charged

anode

which electrode is positively charged

electrolyte

in electrolysis, which is the substance that contains a molten liquid or a solution

direct

what type of current is used in electrolysis

graphite

what is usually used as an electrode

cathode

at which electrode does reduction happen, with the gain of electrons

anode

at which electrode does oxidation happen, with the loss of electrons

the sides

in the extraction of aluminium from bauxite, where are the cathodes that aluminium forms at

the middle

in the extraction of aluminium from bauxite, where are the anodes that oxygen forms at

co2

what forms at the anodes in the extraction of aluminium that mean the graphite has to be replaced

cryolite

what is aluminium dissolved in to lower its boiling point so it can be extracted more efficientyl==ly

hydrogen

in the electrolysis of solutions, what usually forms at the negative electrode (cathode)

copper silver gold platinum

in the electrolysis of solutions, what can also form at the negative electrode (cathode)

halogens

in the electrolysis of solutions, what will always form at the positive electrode (anode) if they are present

oxygen

in the electrolysis of solutions, what will form at the positive electrode (cathode) if there is no group 7 element present

coating metal

in electroplating, what is the positive electrode (anode) made of

object

in electroplating, what is the negative electrode (cathode) made of

metal solution

in electroplating, what should the electrolyte contain

impure

in the purification of metals, what type of metal is the positive electrode (anode) made of

pure

in the purification of metals, what type of metal is the negative electrode (cathode) made of

copper sulfate

what is the electrolyte when copper is being purifyed

sludge

what do the impurities from the copper form at the end of copper purification using electrolysis

anode

which electrode will gain mass when a metal is purifyed

melting point

what decreases as you go down the elements in a group

potassium

what produces a lilac flame both when reacted with water and during a flame test

1

which group of elements are shiny when cut

hydrogen

what gas is always produced when a metal reacts with water to produce an alkaline solution

reactivity

what increases as you go down the elements in a group

transition

which metals have a higher density, higher melting points, are less reactive, act as catalysts, form coloured compounds and ions with different charges

fluorine

which halogen is pale yellow as a gas at room temperature and yellow as a vapour