1. C1 1.1 ATOMS, ELEMENTS & COMPOUNDS All substances are made of atoms Elements are made of only one type of atom Compounds contain more than one type of atom Compounds are held together by bonds Each element has its own symbol in the periodic table Columns are called GROUPS. Elements in a group have similar properties Rows are called PERIODS The red staircase splits metals from non-metals An atom is made up of a tiny nucleus with electrons around it

2. C1 1.2 ATOMIC STRUCTURE Atoms contain PROTONS, NEUTRONS & ELECTRONS Protons and Neutrons are found in the NUCLEUS Electrons orbit the nucleus ATOMIC NUMBER  the number of protons in the nucleus  the periodic table is arranged in this order MASS NUMBER  the number of protons plus neutrons Number of neutrons = Mass Number – Atomic Number Any atom contains equal numbers of protons and electrons PARTICLERELATIVE CHARGE RELATIVE MASS Proton+1 (positive)1 Neutron0 (neutral)1 Electron-1 (negative)0

3. C1 1.3 ELECTRON ARRANGEMENT Electrons are arranged around the nucleus in SHELLS (or energy levels) The shell closest to the nucleus has the lowest energy Electrons occupy the lowest available energy level Atoms with the same number of electrons in the outer shell belong to the same GROUP in the periodic table Number of outer electrons determine the way an element reacts Atoms of the last group (noble gases) have stable arrangements and are unreactive This is how we draw atoms and their electrons Low energy shell High energy shell Sodium

4. C1 1.4 FORMING BONDS Atoms can react to form compounds in a number of ways: i)Transferring electrons  IONIC BONDING ii)Sharing electrons  COVALENT BONDING IONIC BONDING When a metal and non-metal react Metals form positive ions Non-metals from negative ions Opposite charges attract A giant lattice is formed COVALENT BONDING When 2 non-metals bond Outermost electrons are shared A pair of shared electrons forms a bond CHEMICAL FORMULAE Tells us the ratio of each element in the compound In ionic compounds the charges must cancel out: E.g. MgCl 2 We have 2 chloride ions for every magnesium ion

5. H 2 + O 2  H 2 O Add a 2 to the products side to make the oxygen balance H 2 + O 2  2H 2 O This has changed the number of hydrogen atoms so we must now adjust the reactant side: 2H 2 + O 2  2H 2 O C1 1.5 CHEMICAL EQUATIONS Chemical equations show the reactants (what we start with) and the products (what we end up with) We often use symbol equations to make life easier CaCO 3  CaO + CO 2 MAKING EQUATIONS BALANCE Equations MUST balance We can ONLY add BIG numbers to the front of a substance We can tell elements within a compound by BIG letters CaCO 3  this is a compound made of 3 elements (calcium, carbon and oxygen) Ca = 1 C = 1 O = 3 Ca = 1 C = 1 O = 3 This is balanced – same number of each type of atom on both sides of the equation We can check this by counting the number of each type on either side H = 2 O = 2 H = 2 O = 1 H = 2 O = 2 H = 4 O = 2

6. C1 2.1 LIMESTONE & ITS USES Limestone is made mainly of Calcium Carbonate Calcium carbonate has the chemical formulae CaCO 3 Some types of limestone (e.g. chalk) were formed from the remains of animals and plants that live millions of years ago USE IN BUILDING We use limestone in many buildings by cutting it into blocks. Other ways limestone is used: Cement = powdered limestone + powdered clay Concrete = Cement + Sand + Water HEATING LIMESTONE Breaking down a chemical by heating is called THERMAL DECOMPOSITION Calcium  Calcium + Carbon Carbonate Oxide Dioxide CaCO 3  CaO + CO 2 ROTARY LIME KILN This is the furnace used to heat lots of calcium carbonate and turn it into calcium oxide Calcium oxide is used in the building and agricultural industries

7. C1 2.2 REACTIONS OF CARBONATES Buildings made from limestone suffer from damage by acid rain This is because carbonates react with acid to form a salt, water and carbon dioxide Calcium + Hydrochloric  Calcium + Water + Carbon Carbonate Acid Chloride Dioxide CaCO 3 + 2HCl  CaCl 2 + H 2 O + CO 2 TESTING FOR CO 2 We use limewater to test for CO 2 Limewater turns cloudy A precipitate (tiny solid particles) of calcium carbonate forms causing the cloudiness! HEATING CARBONATES Metal carbonates decompose on heating to form the metal oxide and carbon dioxide MgCO 3  MgO + CO 2

8. C1 2.3 THE LIMESTONE REACTION CYCLE Limestone is used widely as a building material We can also use it to make other materials for the construction industry Calcium Carbonate + Heat  Calcium Oxide Calcium Oxide + Water  Calcium Hydroxide (Limewater) Calcium Carbonate Calcium Oxide Calcium Hydroxide Calcium Hydroxide Solution Step 1: Add Heat CaCO 3  CaO + CO 2 Step 2: Add a bit of water CaO + H 2 O  Ca(OH) 2 Step 3: Add more water & filter Ca(OH0) 2 + H 2 O  Ca(OH) 2 (aq) Step 4: Add CO 2 Ca(OH) 2 + CO 2  CaCO 3 + H 2 O Limestone

9. C1 2.4 CEMENT & CONCRETE CEMENT Made by heating limestone with clay in a kiln MORTAR Made by mixing cement and sand with water CONCRETE Made by mixing crushed rocks or stones (called aggregate), cement and sand with water C1 2.5 LIMESTONE ISSUES BENEFITS Provide jobs Lead to improved roads Filled in to make fishing lakes or for planting trees Can be used as landfill sites when finished with DRAWBACKS Destroys habitats Increased emissions Noisy & Dusty Dangerous areas for children Busier roads Ugly looking

10. C1 3.1 EXTRACTING METALS A metal compound within a rock is called an ORE The metal is often combined with oxygen Ores are mined from the ground and then purified Whether it’s worth extracting a particular metal depends on:  How easy it is to extract  How much metal the ore contains The reactivity series helps us decide the best way to extract a metal:  Metals below carbon in the series can be reduced by carbon to give the metal element  Metals more reactive than carbon cannot be extracted using carbon. Instead other methods like ELECTROLYSIS must be used THE REACTIVITY SERIES

11. C1 3.2 IRON & STEELS Iron Ore contains iron combined with oxygen We use a blast furnace and carbon to extract it (as it’s less reactive than carbon) Carbon REDUCES the iron oxide; Iron (III) Oxide + Carbon  Iron + Carbon Dioxide Iron from the blast furnace contains impurities:  Makes it hard and brittle  Can be run into moulds to form cast iron  Used in stoves & man-hole covers Removing all the carbon impurities gives us pure iron  Soft and easily shaped  Too soft for most uses  Need to combine it with other elements A metal mixed with other elements is called an ALLOY E.g. Steel  Iron with carbon and/or other elements There are a number of types of steel alloys:  Carbon steels  Low-alloy steels  High-alloy steels  Stainless steels

12. C1 3.3 ALUMINIUM & TITANIUM AluminiumTitanium Property Shiny Light Low density Conducts electricity and energy Malleable – easily shaped Ductile – drawn into cables and wires Strong Resistant to corrosion High melting point – so can be used at high temperatures Less dense than most metals Use Drinks cans Cooking foil Saucepans High-voltage electricity cables Bicycles Aeroplanes and space vehicles High-performance aircraft Racing bikes Jet engines Parts of nuclear reactors Replacement hip joints Extraction Electrolysis Aluminium ore is mined and extracted. Alumminium oxide (the ore) is melted Electric current passed through at high temperature  Expensive process – need lots of heat and electricity Displacement & Electrolysis Use sodium or potassium to displace titanium from its ore Get sodium and magnesium from electrolysis  Expensive – lots of steps involved, & needs lots of heat and electricity

13. C1 3.4 EXTRACTING COPPER COPPER-RICH ORES These contain lots of copper. There are 2 ways to consider: 1. Smelting 80% of copper is produced this way Heat copper ore strongly in a furnace with air Copper + Oxygen  Copper + Sulphur Sulphide Dioxide Then use electrolysis to purify the copper Expensive as needs lots of heat and electricity 2. Copper Sulphate Add sulphuric acid to a copper ore Produces copper sulphate Extract copper using electrolysis or displacement LOW GRADE COPPER ORES These contain smaller amount of copper. There are 2 main ways: 1. Phytomining Plants absorb copper ions from low-grade ore Plants are burned Copper ions dissolved by adding sulphuric acid Use displacement or electrolysis to extract pure copper 2. Bioleaching Bacteria feed on low-grade ore These produce a waste product that contains copper ions Use displacement or electrolysis to extract pure copper

14. C1 3.5 USEFUL METALS TRANSITION METALS Found in the central block of the periodic table Properties: Good conductors of electricity and energy Strong Malleable – easily bent into shape Uses: Buildings Transport (cars, trains etc) Heating systems Electrical wiring Example: Copper 1.Water pipes – easily bent into shape, strong, doesn’t react with water 2.Wires – ductile and conduct electricity COPPER ALLOYS Bronze – Copper + Tin - Tough - Resistant to corrosion Brass – Copper + Zinc - Harder but workable ALUMINIUM ALLOYS Alloyed with a wide range of other elements All have very different properties E.g. in aircraft or armour plating! GOLD ALLOYS Usually add Copper to make jewellery last longer

15. C1 3.6 METALLIC ISSUES EXPLOITING ORES Mining has many environmental consequences: Scar the landscape Noisy & Dusty Destroy animal habitats Large heaps of waste rock Make groundwater acidic Release gases that cause acid rain RECYCLING METALS Recycling aluminium saves 95% of the energy normally used to extract it! This saves money! Iron and steel are easily recycled. As they are magnetic they are easily separated Copper can be recycled too – but it’s trickier as it’s often alloyed with other elements BUILDING WITH METALS Benefits Steel is strong for girders Aluminium is corrosion resistant Many are malleable Copper is a good conductor and not reactive Drawbacks Iron & steel can rust Extraction causes pollution Metals are more expensive than other materials like concrete