Year 10

1. Year 10 More H please! Metal chemistry.

2. SLO’s • Name and locate various groups of elements on the periodic table. • Be able to draw the first 20 elements by using their atomic number and mass as an indicator of their subatomic particles. • Explain how to predict what ions will be made from the first 20 elements. • Explain what an isotope it and how they are identified. • Describe the six properties that metals have in common. • Carry out the pop test for hydrogen, glowing splint test for oxygen and the flaming splint test for carbon dioxide. • Use the rules; MOMO, MASH & MWMHH to explain how metals react with oxygen, acid and water. • Use the “Stop, swap and drop” method of predicting the products of these metal reactions. • Design a fair test on factors affecting reaction rates using the reaction of calcium carbonate with acid. • Relate the findings of their experiment to collision theory and explain how collision theory applies to temperature, concentration, surface area & catalysts

3. The periodic table. • Can you remember the first 20 elements, in order, from our last Chemistry topic? • Do you remember the periodic patterns? • Let’s review!

5. Rows. • Rows are called periods - elements have the same number of orbital shells and these a filled progressively from left to right • Atomic number increases are you go left to right in a row

6. Columns. • Columns are called groups – elements all have the same number of electrons in their outer shell • Atomic number increases as you go down a column

7. Properties are shared. • Elements in a group have the same number of outer electrons therefore have similar chemical properties. • These groups have names and are normally coloured differently on the periodic table.

8. Group 1. • Alkali metals; all shiny and light metals • Doesn’t include Hydrogen • They are one electron away from being stable (full shells). • A strong chemical desire to give away that 1 electron, means they are very reactive!

9. Group 2. • Alkali Earth metals; all shiny light metals. • Reactive with water, oxygen and acid. • They are 2 electrons away from being stable. • Strongly basic • Tend to occur in nature as compounds.

10. Transition metals. • Are in the middle • Often good conductor of electricity & heat. • Some are highly coloured and/or precious • E.g. copper, silver, gold They are special because the can have more than eight electrons in the outer shell one in from the outermost shell (variable valenacy).

11. Non metals. • On the right hand side of the table. • Tend to be insulators (don’t conduct heat & electricity). • Tend to be brittle. • Non metallic in colour, can be solids or gases at room temperature.

12. Noble gases. • Column 18. • All have full outer shells of electrons, so are not reactive. • Often called inert gases. • Do not make ions. • All are gases at room temperature.

13. What do the atoms of an element look like? • In order to draw an atom, you must know its atomic number & atomic mass. 3 Li 7 Atomic number Number of p & e Symbol Atomic mass Number of p + n

14. Working it out. • Lithium has 3 protons and 3 electrons (atomic number). • Lithium has 4 neutrons (mass-number). • As the first electron shell can only hold 2 electrons, it will have an arrangement of 2,1.

15. Lithium

16. Carbon

17. Drawing the first 20 elements. • For each element, write the number of p & n into the nucleus (central circle). • Then place the electrons in the shells, following the 2,8,8 rule. • What patterns do you see? • The number of protons… • The number of electrons…

18. What about ions? • When an atom loses or gains electrons, it either fills or empties its outer (valence) shell. • It does this to become more stable. • When an atom gains electrons, it becomes negatively charged (as it now has more electrons than protons). • If it gains 1e it is X-, if it gains 2e it is X2-, if it gains 3e it is X3-. • These are called anions.

19. If an atom loses electrons, it becomes positively charged (as it now has more protons than electrons). • If it loses 1e it is Y+, if it loses 2e it is Y2+, if it loses 3e it is Y3+. • These are called cations. • Atoms with 4 electrons in the valence shell, will not gain or lose electrons, they will share with another atom.

20. Predicting ions. • If the atom has 1,2 or 3 electrons in the outer shell, it will lose them. • If the atom has 5,6 or 7 electrons in the outer shell, it will gain them. • If the atom has 4 electrons in the outer shell, it will not form an ion.

21. Naming ions. • When an atom becomes an ion, it sometimes changes its name (like getting married)! • If the ion is alone, it changes to become an -ide. • Sulphide S2-, Oxide O2-, Iodide I-. • If the ion bonds with oxygen, it changes its name to an –ate. • Sulphate SO42-, Nitrate NO32-.

22. If ions bond together in a polyatomic ion, they also change their name. • Hydroxide OH-, Ammonium NH4+. • Oxygen ate an atom, but I’de rather be alone. Chloride

23. Ions love to bond! • Opposites attract in ionic chemistry. • Li+ wants to bond with a negative ion. • When Li+ bonds with Cl- they form LiCl; an ionic compound. • The rule with ionic bonding is; When you see ions, you must STOP, SWAP& DROP!

24. The rules. • Same charge; combine symbols to make the compound formula. • H+ + Cl- HCl • Mg2+ + O2-MgO Cl H

25. Different charges; swap and drop the numbers and lose the charge. • H+ + O2- H20 • Fe3+ + S2-Fe2S3 • This is so you have an equal number of negative and positive charges. H H O

26. Different charges with polyatomic ions; use brackets when there is more than 1 polyatomic ion. • Pb2+ + PO43+ Pb3(PO4)2 • Al3+ + NO3- Al(NO3)3 You must keep polyatomic ions together with brackets.

27. Complete… The table of ions.

28. Mystery ions… • Scientists have discovered two mystery ions X & Y. • They are found in the first 20 elements. • When combined with OH- ions it becomes X(OH)3. • What is ion X? • Ion Y combines with Li+to become Li2Y. • What is ion Y?

29. Isotopes. • An atom of an element, with more or less neutrons than usual. • Doesn’t effect the charge of the atom, only its mass. • Protons & neutrons have a mass of 1, electrons have so little mass, they don’t contribute. C12 and C14are isotopes of carbon. C12 - 6p, 6n, 6e C14 - 6p, 8n, 6e

30. Identifying isotopes. • Atoms can be identified using a mass spectrometer; this machine detects the mass of an atom. • Could it tell the difference between; C12 and C14 ? • Could it tell the difference between; N14and C14 ?

31. Drawing isotopes. • Draw 3 of the isotopes of Cl; Cl1735 Cl1736 Cl1737

32. 17p 18n 17p 19n 17p 20n

33. Isotope questions. What changes between each isotope? Why does the atomic number stay the same? What does this tell us about the mass of an atom? Do they all form the same ion? Why or why not? How could you test to see which isotope you have?

34. Review atoms & ions sheet. An electron is the smallest part of an atom (it has a negative charge). They are found in shells orbiting a central nucleus .The nucleuscontains the protons (which have a positive charge) and the neutrons (which have no charge). The mass of the atom is determined by adding the number of protons and neutrons together, since they each have a mass of one. Normal atoms have thesame number of electrons and protons making them neutral (no charge). Electrons are arranged in shells around the central nucleusin a special way; the first shell can hold two electrons, the second can hold eight electrons and the third can hold eight . We call this the 2,8,8 rule.

35. All atoms with the same number of protons are atoms of the same element. However some atoms of an element, have a different number of neutrons. These are called isotopesof the atom. This is why many of the element mass numbers have a decimal point. An atom which has lost or gained electrons is called an ion. Atoms lose or gain electrons from their outeror valence shell. Atoms which gain electrons become a negative ion, while those which lose become a positive ion. These ions are attracted to each other and form ionicbonds.

36. Review atoms, ions & isotopes. • Making gas part 1.

37. Making hydrogen. H H • Mg + HCl  MgCl2 + H2 • Magnesium + hydrochloric acid  Magnesium chloride + hydrogen gas. • Hydrogen is a very light gas, we test for it using the pop test.

38. Making oxygen O O • KMnO4 KMn + 2O2 • Potassium permanganate + heat  potassium magnate + oxygen gas. • We test for oxygen using the glowing splint test.

39. Making carbon dioxide. C O C • CaCO3 + HCl  CaCl2 + CO2 + H2O • Calcium carbonate + hydrochloric acid  calcium chloride + carbon dioxide + water • We test of carbon dioxide using the burning splint test.

40. What happens in a chemical reaction? • In a chemical reaction, old bonds are broken and new ones are formed. • The chemicals which go into a reaction are called the reactants. • The new chemicals which are made in the reaction are called the products. • Hydrochloric acid + Magnesium  Magnesium Chloride + Hydrogen gas • HCl + Mg  MgCl2 + H2

41. The bond between the H and the Cl was broken (taking in heat). • The new bond between Mg and Cl was formed (giving out heat). • The overall reaction was exothermic (heat producing). • We use STOP, SWAP & DROP to work out what the formula of the products would be.

42. Step 1- breaking bonds H Cl H Cl Mg Mg Mg Mg Mg Mg Mg Mg

43. Step 2- making bonds H H H H H H H H H H Mg Cl Mg Cl Cl Cl

44. Balancing a chemical reaction. • As you can see from the example above, there are different numbers of atoms on each side of the reaction (shown by the arrow). • This means the reaction is unbalanced. • To balance the reaction; • Count up the number of atoms on each side of the arrow (do this for each element). HCl + Mg  MgCl2 + H2 1xH, 1xCl, 1xMg 1x Mg, 2xCl, 2xH

45. Add more of the molecule you need, to the side of the equation which has less. HCl + Mg  MgCl2 + H2 HCl • Count up the number of atoms on each side the arrow, if they are the same, add the big numbers by adding how many of each molecule you now have. 2HCl + Mg  MgCl2 + H2 2xH, 2xCl, 1xMg 1x Mg, 2xCl, 2xH

46. The equation is now balanced. • You may need to add molecules to each side of the arrow in order to make them balance. • Keep adding and checking until you have the same number of each element on each side of the arrow.

47. Fe + H2S04 Fe2(SO4)3 + H2 • C2H6 + O2 H2O + CO2 • KOH + H3PO4 K3PO4 + H2O • SnO2 + H2Sn + H2O • NH3 + O2 NO + H2O 6. KNO3 + H2CO3  K2CO3 + HNO3

48. B2Br6+ HNO3 B(NO3)3 + HBr • BF3­ + Li2SO3  B2(SO3)3 + LiF • (NH4)3PO4 + Pb(NO3)4 Pb3(PO4)4 + NH4NO3 • SeCl6 + O2 SeO2 + Cl2 11. SnO2 + H2 → Sn + H2O

49. Changing the rate of chemical reactions. • Change the temperature. • Change the concentration. • Change the surface area. • Use a catalyst.

50. Collision theory. • In order for a reaction to occur, the reactants must have a successful collision. That is, they must hit together hard enough to break old bonds and form new ones. • With every successful collision, a reaction takes place. The more successful collisions, the faster the reaction occurs.