AQA GCSE Atomic Structure and Periodic Table Part 1

Home , Reactivity series

The smallest part of an Have a radius of around 0.1 Before the discovery of the Atom Tiny solid spheres that electron, John Dalton said the element that can exist nanometres and have no charge (0). Pre 1900 could not be divided solid sphere made up the different Around 100 different elements each elements. Contains only one type of Element one is represented by a symbol e.g. O, atom JJ Thompson ‘s experiments Na, Br. 1897 A ball of positive charge showed that showed that an atom ‘plum with negative electrons Atoms, Atoms, Two or more elements Compounds can only be separated must contain small negative compounds Compound pudding’ embedded in it elements and elements chemically combined into elements by chemical reactions. charges (discovery of electrons). - Ernest Rutherford's alpha particle 1909 - - Positively charge nucleus scattering experiment showed Central nucleus Contains protons and neutrons nuclear - + - at the centre surrounded - - that the mass was concentrated at model - negative electrons Electron shells Contains electrons the centre of the atom. Niels Bohr proposed that electrons 1913 Electrons Electronic Max number of orbited in fixed shells; this was Bohr orbit the nucleus at shell electrons supported by experimental Name of Relative Relative model specific distances Particle Charge Mass 1 2 observations. Proton +1 1 2 8

The development of James Provided the evidence to Electronic Neutron 0 1 3 8 structures the model of the atom Chadwick show the existence of neutrons within the nucleus Electron -1 Very small 4 2 A beam of alpha particles are AQA GCSE directed at a very thin gold foil Most of the alpha particles Relative electrical charges of subatomic particles passed right through. Atomic structure - A few (+) alpha particles were - - Mass The sum of the protons and neutrons in the and periodic deflected by the positive 7 number nucleus - + nucleus. table part 1 experiment - Li A tiny number of particles Atomic The number of Number of electrons = 3 - - reflected back from the number protons in the atom number of protons scattering Rutherford's nucleus.

Show chemical reactions - need Law of conservation of mass states Two or more elements or compounds Can be separated by Chemical Mixtures reactant(s) and product(s) energy the total mass of products = the not chemically combined together physical processes. equations always involves and energy change total mass of reactants. Method Description Example Uses words to show reaction Does not show what is Separating an insoluble solid To get sand from a mixture of Word Filtration reactants  products happening to the atoms or the from a liquid sand, salt and water. equations magnesium + oxygen  magnesium oxide number of atoms. To separate a solid from a To obtain pure crystals of sodium Crystallisation Uses symbols to show reaction Shows the number of atoms and solution chloride from salt water. Symbol reactants  products molecules in the reaction, these To separate a solvent from a equations Simple distillation To get pure water from salt water. 2Mg + O  2MgO need to be balanced. solution 2 35 37 Fractional Separating a mixture of liquids To separate the different Atoms of the same element Cl (75%) and Cl (25%) distillation each with different boiling points compounds in crude oil. with the same number of Relative abundance = Isotopes Separating substances that move protons and different (% isotope 1 x mass isotope 1) + (% isotope To separate out the dyes in food 2 x mass isotope 2) ÷ 100 Chromatography at different rates through a Relative colouring. numbers of neutrons

medium mass atomic e.g. (25 x 37) + (75x 35) ÷ 100 = 35.5 better hope – brighter future Alkali metals Noble gases Halogens Elements Elements in the same group have the Elements with similar arranged in same number of outer shell electrons and 1 2 3 4 5 6 7 0 properties are in columns order of atomic elements in the same period (row) have called groups H Transition metals He number the same number of electron shells. Li Be B C N O F Ne

Na Mg Al Si P S Cl Ar Early periodic tables were incomplete, The Periodic K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr Elements arranged in order some elements were placed in table of atomic weight inappropriate groups if the strict order

Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe electrons

of protons, protons, of atomic weights was followed. neutrons and and neutrons

Cs Ba La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn discovery Before Fr Ra Ac Rf Db Sg Bh Hs Mt ? ? ? Elements with properties predicted by Mendeleev were discovered and filled

Metals to the left of this line, non table Left gaps for elements that in the gaps. Knowledge of isotopes metals to the right hadn’t been discovered yet

Form positive ions. explained why order based on atomic Development Development

To the left of Periodic the of Conductors, high melting and Mendeleev Metals the Periodic weights was not always correct. boiling points, ductile, Metals and table malleable. non metals Very reactive with Only have one electron in their outer oxygen, water and To the right of shell. Form +1 ions. Non Form negative ions. Insulators, chlorine the Periodic AQA GCSE metals low melting and boiling points. 7

table 1 Group Negative outer electron is further Group Atomic structure Reactivity increases

Alkali metals Alkali away from the positive nucleus so is down the group and periodic more easily lost. Consist of molecules made of a pair Have seven electrons in their of atoms outer shell. Form -1 ions. table part 2

Melting and boiling points increase With Forms a metal Metal + oxygen  e.g. 4Na + O2  down the group (gas  liquid  Increasing atomic mass number. Group 0 Transition metals oxygen oxide metal oxide 2Na2O

Halogens solid) (Chemistry only) Forms a metal Metal + water  With e.g. 2Na + 2H O  Increasing proton number means hydroxide and metal hydroxide + 2 Reactivity decreases down the group water 2NaOH + H an electron is more easily gained hydrogen hydrogen 2

e.g. NaCl Metal + halogen  metal This is due With Forms a metal Metal + chlorine  e.g. 2Na + Cl  metal atom loses 2 Forms a metal halide Unreactive, to having chlorine chloride metal chloride 2NaCl outer shell electrons halide e.g. Sodium + chlorine  do not form full outer and halogen gains an sodium chloride molecules shells of Withmetals outer shell electron electrons. 2+ • Less reactive • Cu is blue Hydrogen + halogen  Compared • Harder • Ni2+ is pale green, used in the Forms a hydrogen hydrogen halide to group 1 • Denser e.g. Cl2 + H2  2HCl • Higher melting points manufacture of margarine

With halide e.g. Hydrogen + bromine Noble gases hydrogen  hydrogen bromide Boiling • Fe2+ is green, used in the points Increasing • Many have different ion A more reactive Haber process increase atomic possibilities with different halogen will Chlorine + potassium Typical charges e.g. Cl2 +2KBr 2KCl down the number. 3+ displace the less bromide  potassium properties • Used as catalysts • Fe is reddish-brown + Br2 group reactive halogen chloride + bromine • Form coloured compounds halide salt 2+ solution a of • Mn is pale pink

Withaqueous from the salt

better hope – brighter future Alkali metals Noble gases Halogens Elements Elements in the same group have the Elements with similar arranged in same number of outer shell electrons and 1 2 3 4 5 6 7 0 properties are in columns order of atomic elements in the same period (row) have called groups H Transition metals He number the same number of electron shells. Li Be B C N O F Ne

Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe electrons

of protons, protons, of atomic weights was followed. neutrons and and neutrons

Cs Ba La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn discovery Before Fr Ra Ac Rf Db Sg Bh Hs Mt ? ? ? Elements with properties predicted by Mendeleev were discovered and filled

Metals to the left of this line, non table Left gaps for elements that in the gaps. Knowledge of isotopes metals to the right hadn’t been discovered yet

Form positive ions. explained why order based on atomic Development Development

table 1 Group Negative outer electron is further Group Atomic structure Reactivity increases

Melting and boiling points increase With Forms a metal Metal + oxygen  e.g. 4Na + O2  down the group (gas  liquid  Increasing atomic mass number. Group 0 oxygen oxide metal oxide 2Na2O

Halogens solid) Forms a metal Metal + water  With e.g. 2Na + 2H O  Increasing proton number means hydroxide and metal hydroxide + 2 Reactivity decreases down the group water 2NaOH + H an electron is more easily gained hydrogen hydrogen 2

Hydrogen + halogen  Forms a hydrogen hydrogen halide e.g. Cl2 + H2  2HCl

With halide e.g. Hydrogen + bromine Noble gases hydrogen  hydrogen bromide Boiling points Increasing A more reactive increase atomic halogen will Chlorine + potassium e.g. Cl +2KBr 2KCl down the number. displace the less bromide  potassium 2 + Br group

reactive halogen chloride + bromine 2

halide salt solution a of

Withaqueous from the salt

better hope – brighter future Occurs in compounds formed Particles are oppositely from metals combined with (HT only)

Ionic charged ions Melting and non metals. Limitations of simple model: freezing happen at Solid, • There are no forces in the Occurs in most non metallic melting point, s solid Particles are atoms that liquid, model elements and in compounds of boiling and The amount of energy needed share pairs of electrons gas • All particles are shown as non metals. condensing happen for a state change depends on Covalent spheres at boiling point. the strength of forces between l liquid Particles are atoms which particles in the substance. • Spheres are solid Occurs in metallic elements share delocalised and alloys.

Metallic electrons Delocalised electrons g gas Good conductors carry electrical charge Chemical of electricity High melting and boiling Large amounts of energy needed to bonds through the metal. points break the bonds. High melting This is due to the Energy is transferred by and boiling strong metallic Good conductors

The three three The the delocalised points bonds. of thermal energy electrons.

Do not conduct electricity Ions are held in a fixed position in matter of states Atoms are arranged when solid the lattice and cannot move. Pure metals in layers that can can be bent slide over each AQA Metals as conductors and shaped compounds other. BONDING, Do conduct electricity Lattice breaks apart and the ions ionic of Properties when molten or dissolved are free to move. STRUCTURE AND THE PROPERTIES Mixture of two or Harder than pure metals because more elements at atoms of different sizes disrupt Alloys Ionic bonding OF MATTER 1 least one of the layers so they cannot slide

which is a metal over each other. Properties of of Properties

Metal atoms lose electrons and alloys and metals Group 1 metals form +1 ions become positively charged ions Electrons are transferred so Group 2 metals form +2 ions that all atoms have a noble Pure metal Alloy gas configuration (full outer Non metals atoms gain electrons to Group 6 non metals form -2 ions shells). become negatively charged ions

Group 7 non metals form -1 ions

Metallic Metallic bonding

x + x - Dot and x Na x Cl x Na Cl x Ionic compounds cross x x x x x x [ ] [ x x ] diagram (2, 8, 1) (2, 8, 7) (2, 8) (2, 8, 8) Electrons in the outer shell of metal atoms are Giant structure delocalised and free to • Held together by strong of atoms move through the whole electrostatic forces of arranged in a Giant attraction between oppositely structure. This sharing of Structure regular pattern structure charged ions electrons leads to strong • Forces act in all directions in metallic bonds. Na+ Cl- the lattice

better hope – brighter future Very hard. Rigid structure.

Each carbon Solids at Atoms are linked atom is bonded Very high melting point. Strong covalent bonds. Very large room by strong covalent to four others molecules temperature bonds. Does not conduct No delocalised electrons. electricity.

Low melting and Due to having weak Properties of small molecules Diamond Diamond, boiling points. intermolecular Polymers Very high melting Lots of energy needed to break graphite, silicon forces that easily points strong, covalent bonds. dioxide Covalent bonds broken. AQA in the molecule Do not conduct Due to them are strong but BONDING, STRUCTURE structures Dot and cross :

electricity. molecules not covalent Giant + Show which atom the forces between having an overall AND THE PROPERTIES electrons in the bonds come molecules electrical charge. (intermolecular) OF MATTER 2 from are weak Larger molecules Intermolecular - All electrons are identical

Usually gases orUsually liquidsgases have higher forces increase with Size of particles and their

melting and the size of the bonding properties (Chemistry only) Covalent 2D with bonds: boiling points. molecules. Can be small + Show which atoms are bonded molecules together Contains e.g. ammonia - It shows the H-C-H bond Excellent 1 nanometre (1 nm)

Graphene Between 1 and 100 delocalised = 1 x 10-9 metres incorrectly at 90°

conductor. fullerenes nanometres (nm) in electrons. (0.000 000 001m or a size billionth of a metre).

Contains Nanoparticles

strong 3D ball and stick model: Graphene Single layer of Very strong. and graphite one covalent Use of nanoparticles + Attempts to show the H-C-H bonds. bond angle is 109.5° atom thick of electrons pairs share Atoms

Hexagonal rings Healthcare, of carbon atoms cosmetics, Nanoparticles may be toxic to Can be giant with hollow sun cream, people. They may be able to covalent Buckminsterfullerene, shapes. Can also catalysts, enter the brain from the structures C 60 have rings of five deodorants, bloodstream and cause harm. e.g. polymers First fullerene to be (pentagonal) or electronics.

Usually gases orUsually liquidsgases have higher forces increase with

melting and the size of the bonding Covalent Covalent 2D with bonds: boiling points. molecules. Can be small + Show which atoms are bonded molecules together Contains e.g. ammonia - It shows the H-C-H bond Excellent delocalised Graphene incorrectly at 90°

conductor. fullerenes electrons.

Contains

strong 3D ball and stick model: Graphene Single layer of Very strong. and graphite one covalent + Attempts to show the H-C-H bonds. bond angle is 109.5° atom thick of electrons pairs share Atoms

Hexagonal rings of carbon atoms Can be giant with hollow covalent Buckminsterfullerene, shapes. Can also structures C 60 have rings of five e.g. polymers First fullerene to be (pentagonal) or

Fullerenes discovered. seven Graphite (heptagonal) carbon atoms. Layers can slide over each Each carbon atom is Slippery. other. Very conductive. Used in electronics bonded to three industry. others forming Very thin and Very high melting High tensile strength. Reinforcing layers of hexagonal Strong covalent bonds. long point. composite materials. rings with no cylindrical covalent bonds Does conduct Delocalised electrons fullerenes Large surface area to Catalysts and between the layers electricity. between layers. Carbon nanotubes volume ratio. lubricants. better hope – brighter future The sum of the M of the 2Mg + O  2MgO The sum of the relative r 2 reactants in the quantities The reactant that is Limits the amount of Less moles of product atomic masses of the M shown equals the sum of 48g + 32g = 80g completely used up product that is made are made. r atoms in the numbers the M of the products in shown in the formula r

the quantities shown. 80g = 80g Chemical measurements Whenever a 1. Calculate the mean

Limiting reactants measurement is Can determine 2. Calculate the range Mass appears to Relative formula One of the reactants taken, there is whether the mean of the results

increase during a Magnesium + oxygen  magnesium oxide mass (M is a gas (HTonly) always some value falls within the 3. Estimate of reaction uncertainty range of uncertainty uncertainty in mean Mass appears to One of the products about the result of the result would be half the

decrease during a is a gas and has Calcium carbonate  carbon dioxide + calcium oxide r obtained range ) reaction escaped Example: Mass changes when a reactant or product is a gas Concentration of 1. Mean value is 46.5s solutions 2. Range of results is 44s to 49s = 5s 3. Time taken was 46.5s ±2.5s No atoms are lost or AQA GCSE Conservation Mass of the products equals HT only made during a Measured in of mass the mass of the reactants. QUANTITATIVE CHEMISTRY 1 Greater mass = higher chemical reaction mass per given Conc. = mass (g) . 3 concentration.

equations (HTonly) volume of volume (dm ) Conservation of mass and and balanced symbol Greater volume = lower

solution (g/dm3)

substances in Moles Moles (HTonly) Represent H2 + Cl2  2HCl Amounts of concentration.

chemical equations reactions and Subscript Normal script have the same The balancing numbers in a Convert the masses in grams to number of Subscript numbers show the number of symbol equation can be amounts in moles and convert

atoms of each atoms of the element to its left. only) (HT calculated from the masses of the number of moles to simple equations

element on both to moles Using reactants and products whole number ratios. balance equations equations balance Balanced symbol Balanced symbol sides of the Normal script numbers show the number of equation molecules. If you have a 60g of Mg, what mass of Chemical amounts are One mole of H O = 18g (1 + 1 + 16) HCl do you need to convert it to MgCl ? Mass of one mole of a substance in grams 2 2 measured in moles = relative formula mass (mol) One mole of Mg = 24g Ar : Mg =24 so mass of 1 mole of Mg = 24g M : HCl (1 + 35.5) so mass of 1 mole of Mg + 2HCl  MgCl + H r 6.02 x 1023 per mole 2 2 HCl = 36.5g One mole of any substance will contain the same number of particles, One mole of magnesium reacts One mole of H O will contain 6.02 x 1023 molecules So 60g of Mg is 60/24 = 2.5 moles

atoms, molecules or ions. 2 with two moles of hydrochloric constant Avogadro One mole of NaCl will contain 6.02 x 1023 Na+ ions acid to make one mole of magnesium chloride and one Balanced symbol equation tells us that mole of hydrogen for every one mole of Mg, you need How many moles of sulfuric acid molecules are there in two moles of HCl to react with it. 4.7g of sulfuric acid (H SO )? Number of moles = mass (g) or mass (g) 2 4 Give your answer to 1 significant figure. So you need 2.5x2 = 5 moles of HCl A M

r r and the number reacting moles ofmade You will need 5 x 36.5g of HCl= 182.5g 4.7 = 0.05 mol equations showChemical number the of moles

98 (Mr of H2SO4) better hope – brighter future The sum of the M of the 2Mg + O  2MgO The sum of the relative r 2 reactants in the quantities atomic masses of the M shown equals the sum of 48g + 32g = 80g r atoms in the numbers the M of the products in shown in the formula r

the quantities shown. 80g = 80g Chemical measurements Whenever a 1. Calculate the mean measurement is Can determine 2. Calculate the range Mass appears to Relative formula One of the reactants taken, there is whether the mean of the results

increase during a Magnesium + oxygen  magnesium oxide mass (M is a gas always some value falls within the 3. Estimate of reaction uncertainty range of uncertainty uncertainty in mean Mass appears to One of the products about the result of the result would be half the

volume of volume (dm3) Conservation of mass and and balanced symbol Greater volume = lower solution (g/dm3) Represent H2 + Cl2  2HCl concentration.

chemical equations reactions and Subscript Normal script have the same number of Subscript numbers show the number of atoms of each atoms of the element to its left. equations element on both Balanced symbol Balanced symbol sides of the Normal script numbers show the number of equation molecules.

better hope – brighter future High atom economy is A measure of the amount Atom economy = Relative formula mass of desired product from equation x 100 important or sustainable of starting materials that Sum of relative formula mass of all reactants from equation development and economic end up as useful products reasons

Calculate the atom economy for making hydrogen What is the concentration of a solution that has 35.0g of 3 by reacting zinc with hydrochloric acid: Concentration of a solution Concentration = amount (mol) solute in 0.5dm of solution? is the amount of solute per (mol/dm3) volume (dm3) volume of solution 35/0.5 = 70 g/dm3

Zn + 2HCl → ZnCl2 + H2 Atom economy

Mr of H2 = 1 + 1 = 2 2NaOH(aq) + H2SO4(aq)→ Na2S04(aq) + 2H2O(l) Mr of Zn + 2HCl = 65 + 1 + 1 + 35.5 + 35.5 = 138 Using concentrations of solutions in mol/dm3 It takes 12.20cm3 of sulfuric acid to neutralise 24.00cm3 of If the volumes of sodium hydroxide solution, which has a concentration of Atom economy = 2∕ × 100 (HT only, chemistry only) 138 two solutions that 3 2 0.50mol/dm . = ∕138 × 100 = 1.45% react completely AQA are known and the Calculate the concentration of the sulfuric acid in mol/dm3: concentrations of This method is unlikely to be chosen as it has a QUANTITATIVE one solution is 0.5 mol/dm3 x (24/1000) dm3 = 0.012 mol of NaOH

low atom economy. Titration CHEMISTRY 2 known, the The equation shows that 2 mol of NaOH reacts with 1 mol of concentration of 3 H2SO4, so the number of moles in 12.20cm of sulfuric acid is the other solution HT only: (0.012/2) = 0.006 mol of sulfuric acid can be calculated.

200g of calcium carbonate is heated. It decomposes to make calcium oxide Percentage yield 3 and carbon dioxide. Calculate the theoretical mass of calcium oxide made. Calculate the concentration of sulfuric acid in mol/ dm 0.006 mol x (1000/12.2) dm3 =0.49mol/dm3

CaCO3  CaO + CO2 Mr of CaCO3 = 40 + 12 + (16x3) = 100 Use of amount of substance in Calculate the concentration of sulfuric acid in M of CaO = 40 + 16 = 56 r relation to volumes of gases g/ dm3: 100g of CaCO3 would make 56 g of CaO (HT only, chemistry only) H2SO4 = (2x1) + 32 + (4x16) = 98g So 200g would make 112g 0.49 x 98g = 48.2g/dm3

The reaction may not go to completion because it is Equal amounts of It is not always reversible. moles or gases occupy The volume of one mole of Yield is the possible to obtain the same volume any gas at room temperature No. of moles of gas = vol of gas (dm3) amount of Some of the product may be lost when it is separated the calculated under the same and pressure (20°C and 1 24dm3 product from the reaction mixture. amount of a conditions of atmospheric pressure) is 24 obtained product Some of the reactants may react in ways different to temperature and dm3 the expected reaction. pressure

A piece of sodium metal is heated in 6g of a hydrocarbon gas had a volume of 4.8 dm3. Percentage yield is What is the volume of 11.6 g of chlorine gas. A maximum theoretical Calculate its molecular mass. comparing the butane (C4H10) gas at RTP? mass of 10g for sodium chloride was amount of product 1 mole = 24 dm3, so 4.8/24 = 0.2 mol % Yield = Mass of product made x 100 calculated, but the actual yield was Mr : (4 x 12) + (10 x 1) = 58 obtained as a Max. theoretical mass only 8g. percentage of the M = 6 / 0.2 = 30 Calculate the percentage yield. 11.6/58 = 0.20 mol r maximum theoretical amount 3 If 6g = 0.2 mol, 1 mol equals 30 g Percentage yield = 8/10 x 100 =80% Volume = 0.20 x 24 = 4.8 dm better hope – brighter future High atom economy is A measure of the amount Atom economy = Relative formula mass of desired product from equation x 100 important or sustainable of starting materials that Sum of relative formula mass of all reactants from equation development and economic end up as useful products reasons

Calculate the atom economy for making hydrogen by reacting zinc with hydrochloric acid:

Zn + 2HCl → ZnCl2 + H2 Atom economy

Mr of H2 = 1 + 1 = 2 Mr of Zn + 2HCl = 65 + 1 + 1 + 35.5 + 35.5 = 138

2 Atom economy = ∕138 × 100 2 = ∕138 × 100 = 1.45% AQA

This method is unlikely to be chosen as it has a QUANTITATIVE low atom economy. CHEMISTRY 2

HT only:

200g of calcium carbonate is heated. It decomposes to make calcium oxide Percentage yield and carbon dioxide. Calculate the theoretical mass of calcium oxide made.

CaCO3  CaO + CO2 Mr of CaCO3 = 40 + 12 + (16x3) = 100 Mr of CaO = 40 + 16 = 56 100g of CaCO3 would make 56 g of CaO So 200g would make 112g

The reaction may not go to completion because it is It is not always reversible. Yield is the possible to obtain amount of Some of the product may be lost when it is separated the calculated product from the reaction mixture. amount of a obtained product Some of the reactants may react in ways different to the expected reaction.

Calculate the atom economy for making hydrogen by reacting zinc with hydrochloric acid:

Zn + 2HCl → ZnCl2 + H2 Atom economy

Mr of H2 = 1 + 1 = 2 Mr of Zn + 2HCl = 65 + 1 + 1 + 35.5 + 35.5 = 138

2 Atom economy = ∕138 × 100 2 = ∕138 × 100 = 1.45% AQA

This method is unlikely to be chosen as it has a QUANTITATIVE

low atom economy. CHEMISTRY 2 Percentage yield

A piece of sodium metal is heated in Percentage yield is chlorine gas. A maximum theoretical comparing the mass of 10g for sodium chloride was amount of product % Yield = Mass of product made x 100 calculated, but the actual yield was obtained as a Max. theoretical mass only 8g. percentage of the Calculate the percentage yield. maximum theoretical amount Percentage yield = 8/10 x 100 =80% better hope – brighter future Oxidation Is Loss (of electrons) Reduction Is Gain (of electrons) HT ONLY: Reactions between metals and acids are redox reactions as the metal donates electrons to the hydrogen ions. This displaces hydrogen as a gas while the metal ions are left in the solution. Ionic half equations (HT only) Reactions magnesium + hydrochloric acid  magnesium chloride + hydrogen metal + acid  metal salt For example: with + hydrogen The ionic equation for the reaction acids zinc + sulfuric acid  zinc sulfate + hydrogen Ionic half between iron and copper (II) ions is: equations show Fe + Cu2+  Fe2+ + Cu For Acids react with some metals to Extraction using carbon what happens displacement produce salts and hydrogen. to each of the The half-equation for iron (II) is: reactions Metals less reactive than reactants during Fe  Fe2+ + 2e- Reactions of acids carbon can be extracted For example: reactions from their oxides by zinc oxide + carbon  zinc + carbon dioxide The half-equation for copper (II) ions is: and metals reduction. Cu2+ + 2e-  Cu Reactions of Oxidation and Extraction of Unreactive metals, such as gold, are found in Acid name Salt name reduction in terms of acids metals and the Earth as the metal itself. They can be mined from the ground. Hydrochloric electrons (HT ONLY) reduction Chloride acid AQA Chemical Reactions with water Reactions with acid Changes 1 Sulfuric acid Sulfate Neutralisation of acids Reactions get more Reactions get more and salt production Group 1 metals vigorous as you go down vigorous as you go down Nitric acid Nitrate Reactivity of the group the group metals Observable reactions Group 2 metals Do not react with water include fizzing and sodium hydroxide + hydrochloric acid  sodium chloride + water temperature increases calcium carbonate + sulfuric acid  calcium sulfate, + carbon dioxide + water The reactivity series Zinc and iron react slowly Zinc, iron and Do not react with water with acid. Copper does not Metal copper Acids can An alkali is a soluble base e.g. metal react with acid. be hydroxide. oxides Neutralisation neutralised A base is a substance that by alkalis neutralises an acid e.g. a soluble Metals form The reactivity of a The reactivity series arranges and bases metal hydroxide or a metal oxide. positive ions metal is related to its metals in order of their reactivity when they tendency to form (their tendency to form positive react positive ions ions). Metals react with Metals and magnesium + oxygen  magnesium oxide oxygen to form metal These two non-metals are oxygen 2Mg + O  2MgO Carbon and hydrogen oxides 2 included in the reactivity series as Carbon and are non-metals but are they can be used to extract some This is when oxygen is hydrogen included in the removed from a e.g. metal oxides reacting with hydrogen, metals from their ores, depending Reduction reactivity series compound during a extracting low reactivity metals on their reactivity. reaction A more reactive metal Silver nitrate + Sodium chloride  can displace a less This is when oxygen is e.g. metals reacting with oxygen, rusting of Displacement reactive metal from a Oxidation gained by a compound iron Sodium nitrate + Silver chloride during a reaction compound.

better hope – brighter future Oxidation Is Loss (of electrons) Reduction Is Gain (of electrons) HT ONLY: Reactions between metals and acids are redox reactions as the metal donates electrons to the hydrogen ions. This displaces hydrogen as a gas while the metal ions are left in the solution.

Reactions magnesium + hydrochloric acid  magnesium chloride + hydrogen metal + acid  metal salt with + hydrogen acids zinc + sulfuric acid  zinc sulfate + hydrogen

Acids react with some metals to Extraction using carbon produce salts and hydrogen. Metals less reactive than Reactions of acids carbon can be extracted For example: from their oxides by zinc oxide + carbon  zinc + carbon dioxide and metals reduction. Reactions of Extraction of Unreactive metals, such as gold, are found in Acid name Salt name acids metals and the Earth as the metal itself. They can be mined from the ground. Hydrochloric reduction Chloride acid AQA Chemical Reactions with water Reactions with acid Changes 1 Sulfuric acid Sulfate Neutralisation of acids Reactions get more Reactions get more and salt production Group 1 metals vigorous as you go down vigorous as you go down Nitric acid Nitrate Reactivity of the group the group metals Observable reactions Group 2 metals Do not react with water include fizzing and sodium hydroxide + hydrochloric acid  sodium chloride + water temperature increases calcium carbonate + sulfuric acid  calcium sulfate, + carbon dioxide + water The reactivity series Zinc and iron react slowly Zinc, iron and Do not react with water with acid. Copper does not Metal copper Acids can An alkali is a soluble base e.g. metal react with acid. be hydroxide. oxides Neutralisation neutralised A base is a substance that by alkalis neutralises an acid e.g. a soluble Metals form The reactivity of a The reactivity series arranges and bases metal hydroxide or a metal oxide. positive ions metal is related to its metals in order of their reactivity when they tendency to form (their tendency to form positive react positive ions ions). Metals react with Metals and magnesium + oxygen  magnesium oxide oxygen to form metal These two non-metals are oxygen 2Mg + O  2MgO Carbon and hydrogen oxides 2 included in the reactivity series as Carbon and are non-metals but are they can be used to extract some This is when oxygen is hydrogen included in the removed from a e.g. metal oxides reacting with hydrogen, metals from their ores, depending Reduction reactivity series compound during a extracting low reactivity metals on their reactivity. reaction A more reactive metal Silver nitrate + Sodium chloride  can displace a less This is when oxygen is e.g. metals reacting with oxygen, rusting of Displacement reactive metal from a Oxidation gained by a compound iron Sodium nitrate + Silver chloride during a reaction compound.

better hope – brighter future The ions discharged when an aqueous When an ionic compound is melted or dissolved in solution is electrolysed using inert Splitting up water, the ions are free to move. These are then able Process of electrodes depend on the relative using to conduct electricity and are called electrolytes. electrolysis reactivity of the elements involved. electricity Passing an electric current though electrolytes causes Metals can be extracted from molten the ions to move to the electrodes. compounds using electrolysis. Metal will be produced on the electrode At the if it is less reactive than hydrogen. Anode The positive electrode is called the anode. This process is used when the metal is too negative Electrode Hydrogen will be produced if the metal is Cathode The negative electrode is called the cathode. reactive to be extracted by reduction with electrode more reactive than hydrogen. carbon. Cations are positive ions and they move to the Where do The process is expensive due to large

Oxygen is formed at positive electrode. Cations negative cathode. electrolysis At the the ions amounts of energy needed to produce the If you have a halide ion (Cl-, I-, Br-) then Anions Anions are negative ions and they move to the positive go? electrical current.

you will get chlorine, bromine or iodine positive anode. using metals Extracting electrode formed at that electrode. Example: aluminium is extracted in this _ + way. Electrolysis of aqueous solutions Electrolysis

Strong and weak acids Higher tier: You can display what is happening at each electrode using half-equations: + - Bromide ions Br - 2+ - Lead ions Pb + + - At the cathode: Pb + 2e  Pb

Completely ionised in aqueous solutions (HTONLY) AQA Chemical + - - - Strong acids - At the anode: 2Br  Br + 2e + Molten lead (II) 2 e.g. hydrochloric, nitric and sulfuric acids. - Changes 2 + bromide

1. Use the pipette to add 25 cm3 of alkali to a conical flask Only partially ionised in aqueous solutions Weak acids and add a few drops of indicator. e.g. ethanoic acid, citric acid. Reactions of acids Titrations As the pH decreases by one unit (becoming 2. Fill the burette with acid and note the starting volume. Hydrogen ion (Chemistry a stronger acid), the hydrogen ion Slowly add the acid from the burette to the alkali in the concentration only) concentration increases by a factor of 10. conical flask, swirling to mix.

Soluble Soluble salts Titrations are used to work out 3. Stop adding the acid when the end-point is reached (the Soluble salts can be made from reacting the precise volumes of acid and appropriate colour change in the indicator happens). Note acids with solid insoluble substances Soluble salts alkali solutions that react with the final volume reading. Repeat steps 1 to 3 until you get (e.g. metals, metal oxides, hydroxides each other. consistent readings. and carbonates).

Add the solid to the acid until no more Production of The scale pH and

dissolves. Filter off excess solid and then neutralisation soluble salts Calculating the chemical quantities in crystallise to produce solid salts. The equation shows that 2 mol of NaOH reacts titrations involving concentrations in 3 3 with 1 mol of H2SO4, so the number of moles mol/dm and in g/dm 3 You can use universal (HT ONLY): in 12.20cm of sulfuric acid is (0.012/2) = indicator or a pH probe to 0.006 mol of sulfuric acid 2NaOH(aq) + H2SO4(aq)→ Na2S04(aq) + measure the acidity or 2H2O(l) alkalinity of a solution Calculate the concentration of sulfuric acid in 3 against the pH scale. It takes 12.20cm of sulfuric acid to neutralise mol/ dm3 24.00cm3 of sodium hydroxide solution, which 0.006 mol x (1000/12.2) dm3 =0.49mol/dm3 has a concentration of 0.50mol/dm3. Acids produce hydrogen ions (H+) Calculate the concentration of sulfuric acid in Acids In neutralisation reactions, hydrogen in aqueous solutions. Calculate the concentration of the sulfuric acid 3 3 g/ dm ions react with hydroxide ions to in g/dm 3 3 H2SO4 = (2x1) + 32 + (4x16) = 98g produce water: Aqueous solutions of alkalis 0.5 mol/dm x (24/1000) dm = 0.012 mol of 0.49 x 98g = 48.2g/dm3 + - Alkalis - NaOH H + OH  H2O contain hydroxide ions (OH ).

Strong and weak acids Higher tier: You can display what is happening at each electrode using half-equations: + - Bromide ions Br - 2+ - Lead ions Pb + + - At the cathode: Pb + 2e  Pb

Only partially ionised in aqueous solutions Weak acids e.g. ethanoic acid, citric acid. Reactions of acids As the pH decreases by one unit (becoming Hydrogen ion a stronger acid), the hydrogen ion concentration

concentration increases by a factor of 10. Soluble Soluble salts Soluble salts can be made from reacting acids with solid insoluble substances Soluble salts (e.g. metals, metal oxides, hydroxides and carbonates).

Add the solid to the acid until no more Production of The scale pH and

dissolves. Filter off excess solid and then neutralisation soluble salts crystallise to produce solid salts.

You can use universal indicator or a pH probe to measure the acidity or alkalinity of a solution against the pH scale.

Acids produce hydrogen ions (H+) Acids In neutralisation reactions, hydrogen in aqueous solutions. ions react with hydroxide ions to produce water: Aqueous solutions of alkalis + - Alkalis - H + OH  H2O contain hydroxide ions (OH ).

+ - Bromide ions Br - Lead ions Pb + + - AQA Chemical + - - + Molten lead (II) - Changes 2 + bromide

Reactions of

acids Soluble Soluble salts Soluble salts can be made from reacting acids with solid insoluble substances Soluble salts (e.g. metals, metal oxides, hydroxides and carbonates).

Add the solid to the acid until no more Production of The scale pH and

dissolves. Filter off excess solid and then neutralisation soluble salts crystallise to produce solid salts.

You can use universal indicator or a pH probe to measure the acidity or alkalinity of a solution against the pH scale.

better hope – brighter future Energy is taken in from the Negative electrode: Positive electrode: • Thermal decomposition surroundings so the 2H (g) + 4OH- (aq)  4H O (l) + 4e- O (g) + 2H O (l) + 4e-  4OH- (aq) Endothermic • Sports injury packs 2 2 2 2

temperature of the Ionic half surroundings decreases equations

Energy is transferred to the Word equation: Symbol equation: • Combustion surroundings so the Exothermic • Hand warmers temperature of the hydrogen + oxygen  water 2H2 + O2  2H2O • Neutralisation surroundings increases Advantages: Disadvantages: • No pollutants produced • Hydrogen is highly flammable Show the overall energy change of a Reaction • Can be a range of sizes • Hydrogen is difficult to store reaction cellsfuel Hydrogen profiles Types of reaction Fuel cells (Chemistry only) Breaking bonds in reactants Endothermic process The energy AQA GCSE change of Reaction The minimum amount Making bonds in products Exothermic process Chemical reactions only reactions Energy changes profiles of energy that colliding happen when particles (HT only) particles must have in collide with sufficient order to react is called Energy released making new Cells and batteries energy Exothermic bonds is greater than the the activation energy.

(Chemistry only) energy Activation energy taken in breaking existing bonds. Make a simple cell by Energy needed to break existing connecting two different Increase the

of a reaction a of Endothermic bonds is greater than the metals in contact with an voltage by Products are at a higher energy energy released making new level than the reactants. As the

Simple cell electrolyte increasing the Overall energy change change energy Overall bonds. reactivity reactants form products, energy Consist of two or more difference is transferred from the cells connected together between the surroundings to the reaction

in series to provide a two metals. mixture. The temperature of the Batteries Calculate the overall energy change for the greater voltage. Endothermic surroundings decreases because forward reaction energy is taken in during the N2 + 3H2 ⇌ 2NH3 reaction. Bond energies (in kJ/mol): H-H 436, H-N 391, Stop when one of the N≡N 945 reactants has been Alkaline

cells used up batteries Products are at a lower energy rechargeable rechargeable - level than the reactants. When Bond breaking: 945 + (3 x 436) = 945 + 1308 =

Non the reactants form products, 2253 kJ/mol energy is transferred to the Can be recharged surroundings. The temperature Bond making: 6 x 391 = 2346 kJ/mol because the chemical of the surroundings increases Bond calculation energy reactions are reversed Rechargeable

Exothermic because energy is released Overall energy change = 2253 - 2346 = -93kJ/mol when an external batteries during the reaction. electrical current is

Therefore reaction is exothermic overall. supplied Rechargeable cells Rechargeable

better hope – brighter future Energy is taken in from the • Thermal decomposition surroundings so the Endothermic • Sports injury packs temperature of the surroundings decreases

Energy is transferred to the • Combustion surroundings so the Exothermic • Hand warmers temperature of the • Neutralisation surroundings increases

Show the overall energy change of a Reaction reaction profiles Types of reaction Breaking bonds in reactants Endothermic process The energy AQA GCSE change of Reaction The minimum amount Making bonds in products Exothermic process Chemical reactions only reactions Energy changes profiles of energy that colliding happen when particles (HT only) particles must have in collide with sufficient order to react is called Energy released making new energy Exothermic bonds is greater than the the activation energy. energy taken in breaking energy Activation existing bonds. Energy needed to break existing

of a reaction a of Endothermic bonds is greater than the Products are at a higher energy energy released making new level than the reactants. As the

Overall energy change change energy Overall bonds. reactants form products, energy is transferred from the surroundings to the reaction mixture. The temperature of the

Calculate the overall energy change for the Endothermic surroundings decreases because forward reaction energy is taken in during the N2 + 3H2 ⇌ 2NH3 reaction. Bond energies (in kJ/mol): H-H 436, H-N 391, N≡N 945 Products are at a lower energy level than the reactants. When Bond breaking: 945 + (3 x 436) = 945 + 1308 = the reactants form products, 2253 kJ/mol energy is transferred to the surroundings. The temperature

Bond making: 6 x 391 = 2346 kJ/mol of the surroundings increases Bond calculation energy

Exothermic because energy is released Overall energy change = 2253 - 2346 = -93kJ/mol during the reaction.

Therefore reaction is exothermic overall.

better hope – brighter future Energy is taken in from the • Thermal decomposition surroundings so the Endothermic • Sports injury packs temperature of the surroundings decreases

Energy is transferred to the • Combustion surroundings so the Exothermic • Hand warmers temperature of the • Neutralisation surroundings increases

Types of reaction

AQA GCSE Reaction The minimum amount Chemical reactions only Energy changes profiles of energy that colliding happen when particles particles must have in collide with sufficient order to react is called energy

the activation energy. Activation energy Activation

Products are at a higher energy level than the reactants. As the reactants form products, energy is transferred from the surroundings to the reaction mixture. The temperature of the

Endothermic surroundings decreases because energy is taken in during the reaction.

Products are at a lower energy level than the reactants. When the reactants form products, energy is transferred to the surroundings. The temperature of the surroundings increases

Exothermic because energy is released during the reaction.

better hope – brighter future