C1 ATOMIC STRUCTURE AND PERIODIC TABLE

Transcription

1 C ATOMIC STRUCTURE AND PERIODIC TABLE Question Practice Name: Class: Date: Time: 85 minutes Marks: 79 marks Comments: HIGHER TIER Page of 57

2 This question is about calcium. What type of compound is calcium oxide? Tick one box. An acid A base A carbonate A salt () (b) Ionic compounds, such as calcium oxide, have high melting points. Complete the sentences. Use words from the box. bonds forces ions layers Calcium oxide has a giant ionic lattice in which there are strong electrostatic of attraction in all directions. () Page 2 of 57

3 (c) The figure below shows the electronic structure of an oxygen atom and a calcium atom. Describe how the calcium atom and the oxygen atom forms calcium oxide. You should give the charge on each ion formed. (4) (Total 6 marks) Page 3 of 57

4 2 Figure shows a reactor used to produce titanium from titanium(iv) chloride. Figure The chemical equation for the reaction of titanium(iv) chloride with sodium is: TiCl 4 + 4Na Ti + 4NaCl titanium(iv) chloride + sodium titanium + sodium chloride For one reaction: 65 kg titanium(iv) chloride reacted completely with 782 kg sodium 989 kg sodium chloride was produced. Calculate the mass of titanium produced from this reaction. Mass of titanium = kg () Page 4 of 57

5 (b) The table below shows the solubility of sodium chloride in 00 cm 3 of aqueous solution at different temperatures. Solubility of sodium chloride in g per 00cm 3 Temperature in C On Figure 2: plot this data on the grid draw a line of best fit. Figure 2 (3) Page 5 of 57

6 Volume of water = dm 3 (2) (c) The product sodium chloride is dissolved in water to separate it from titanium. At 30 C the solubility of sodium chloride is 36 kg per 00 dm 3. Calculate the minimum volume of water in dm 3, at 30 C, needed to dissolve 989 kg sodium chloride. (d) Calculate the percentage by mass of titanium in titanium(iv) chloride (TiCl 4 ). Give your answer to 3 significant figures. Relative atomic masses (A r ): Cl = 35.5; Ti = 48 Percentage of titanium by mass = % (3) (e) Suggest why the reaction is done in an atmosphere of dry argon instead of air containing water vapour. (3) Page 6 of 57

7 (f) Explain why titanium conducts electricity. (3) (Total 5 marks) Page 7 of 57

8 3 A student used paper chromatography to identify the pigments in spinach leaves. She used propanone as a solvent. Figure shows the student s results. Figure Name the mobile phase and the stationary phase in the student s experiment. Mobile phase Stationary phase (2) Page 8 of 57

9 (b) What does Figure tell you about the green pigment from spinach? (3) (c) Write the equation that links distance moved by solvent, distance moved by solute and R f value. () (d) Use Figure to calculate the R f value for pigment B. R f value = (3) Page 9 of 57

10 (e) Another student set up the apparatus shown in Figure 2. Figure 2 This student did not set up the apparatus correctly. Identify the errors the student made. Explain how the errors she made would affect her results. (4) (Total 3 marks) Page 0 of 57

11 4 This question is about magnesium. (i) The electronic structure of a magnesium atom is shown below. Use the correct answer from the box to complete each sentence. electrons neutrons protons shells The nucleus contains protons and The particles with the smallest relative mass that move around the nucleus are called Atoms of magnesium are neutral because they contain the same number of electrons and (3) (ii) A magnesium atom reacts to produce a magnesium ion. Which diagram shows a magnesium ion? Tick ( ) one box. () Page of 57

12 (b) Magnesium and dilute hydrochloric acid react to produce magnesium chloride solution and hydrogen. Mg(s) + 2 HCl(aq) MgCl 2 (aq) + H 2 (g) (i) State two observations that could be made during the reaction.. 2. (2) (ii) In this question you will be assessed on using good English, organising information clearly and using specialist terms where appropriate. Describe a method for making pure crystals of magnesium chloride from magnesium and dilute hydrochloric acid. In your method you should name the apparatus you will use. You do not need to mention safety. (6) (Total 2 marks) Page 2 of 57

13 5 This question is about atomic structure and elements. Complete the sentences. (i) (ii) The atomic number of an atom is the number of The mass number of an atom is the number of () () (b) Explain why an atom has no overall charge. Use the relative electrical charges of sub-atomic particles in your explanation. (2) (c) Explain why fluorine and chlorine are in the same group of the periodic table. Give the electronic structures of fluorine and chlorine in your explanation. (2) Page 3 of 57

14 (d) The diagram shows the electronic structure of an atom of a non-metal. What is the chemical symbol of this non-metal? Tick ( ) one box. Ar O S Si () (e) When elements react, their atoms join with other atoms to form compounds. Complete the sentences. (i) Compounds formed when non-metals react with metals consist of particles called. () (ii) Compounds formed from only non-metals consist of particles called. () (Total 9 marks) Page 4 of 57

15 6 This question is about atoms and isotopes. Atoms contain protons, neutrons and electrons. A lithium atom has the symbol Explain, in terms of sub-atomic particles, why the mass number of this lithium atom is 7. (3) (b) Amounts of substances can be described in different ways. Complete the sentences. One mole of a substance is the relative formula mass in The relative atomic mass of an element compares the mass of an atom of an element with the mass of an atom of (2) (c) Two isotopes of oxygen are and Describe the similarities and differences between the isotopes and You should refer to the numbers of sub-atomic particles in each isotope. (3) (Total 8 marks) Page 5 of 57

16 7 In 866 John Newlands produced an early version of the periodic table. Part of Newlands periodic table is shown below. Column H Li Be B C N O F Na Mg Al Si P S Cl K Ca Cr Ti Mn Fe Newlands periodic table arranged all the known elements into columns in order of their atomic weight. Newlands was trying to show a pattern by putting the elements into columns. Iron (Fe) does not fit the pattern in column 7. Give a reason why. () (b) In 869 Dmitri Mendeleev produced his version of the periodic table. Why did Mendeleev leave gaps for undiscovered elements in his periodic table? () (c) Newlands and Mendeleev placed the elements in order of atomic weight. Complete the sentence. The modern periodic table places the elements in order of. () Page 6 of 57

17 (d) Lithium, sodium and potassium are all in Group of the modern periodic table. Explain why. (2) (Total 5 marks) 8 This question is about the halogens (Group 7). How do the boiling points of the halogens change down the group from fluorine to iodine? () (b) Sodium bromide is produced by reacting sodium with bromine. Sodium bromide is an ionic compound. (i) Write down the symbols of the two ions in sodium bromide. () (ii) Chlorine reacts with sodium bromide solution to produce bromine and one other product. Complete the word equation for the reaction. chlorine + sodium bromide bromine + () (iii) Why does chlorine displace bromine from sodium bromide? () (iv) Use the Chemistry Data Sheet to help you to answer this question. Suggest which halogen could react with sodium chloride solution to produce chlorine. () (Total 5 marks) Page 7 of 57

18 9 The positions of eight elements in the modern periodic table are shown below. Choose the correct chemical symbols to complete each sentence. The two metals that react vigorously with water are and. (b) The element used as a catalyst in the Haber process is. () () (c) The two elements with five electrons in their outer shell (highest energy level) are and. () (d) Iron has ions with different charges. The other metal that has ions with different charges is. () (Total 4 marks) Page 8 of 57

19 0 Elements are made up of atoms. What is the approximate radius of an atom? Tick one box. 0 m 0 m 0 0 m 0 00 m () (b) The figure below shows the atoms of five elements. The letters are not the symbols of these elements. Complete the sentence. All of the elements in the figure above are in Group of the periodic table. () (c) Which two atoms in the figure above are isotopes of the same element? Explain your answer fully. (3) Page 9 of 57

20 (d) The halogens are in Group 7 of the periodic table. Explain the trend in reactivity of the halogens. (6) (Total marks) The figure below shows a simple model of the three states of matter. What is the correct equation to work out the density of a material? () (b) A student explains density to his teacher using the particle model in the figure above. His teacher says there are limitations to the model. Give two limitations of the particle model in the figure above.. 2. (2) Page 20 of 57

21 (c) When the gas in a container with a fixed volume is heated, the pressure increases as the temperature increases. Explain why the pressure increases. Use the model in the figure above to help you. (4) (Total 7 marks) Page 2 of 57

22 2 Figure shows the plum pudding model of the atom. This model was used by some scientists after the discovery of electrons in 897. Figure Plum-pudding model In 9 the scientists Geiger and Marsden investigated the effect of firing alpha particles at very thin sheets of gold foil. Their experiment is shown in Figure 2. The arrows show the paths taken by alpha particles in the experiment. Figure 2 Explain why scientists replaced the plum pudding model of the atom with the nuclear model of the atom as a result of the experiment. (4) Page 22 of 57

23 (b) According to modern measurements: the radius of an atom is about 0 0 m the radius of an atomic nucleus is about 0 4 m Show that these values fit with the nuclear model of the atom. (2) (c) In 93 a scientist discovered that there are hydrogen atoms with mass number 2 as well as hydrogen atoms with mass number. A year later, another scientist discovered neutrons. Explain why the discovery of neutrons could explain the presence of hydrogen atoms with different mass numbers. (3) (d) How would the results of the experiment shown in Figure 2 change if neutrons were used instead of alpha particles to bombard a thin sheet of gold? (2) (Total marks) Page 23 of 57

24 3 In 869 there were 60 known elements. Mendeleev arranged the elements in order of their atomic mass (atomic weight). He realised that elements with similar properties occurred at regular intervals. Suggest why one of the groups that is on today s periodic table was not in Mendeleev s periodic system. () (b) Explain the arrangement of the first 20 elements in today s periodic table. You should answer in terms of atomic structure. (2) Page 24 of 57

25 (c) A student put some potassium bromide solution in a test tube. She added a few drops of chlorine solution and observed the result. She repeated the process using different potassium halide salts and different halogens. The table below shows the student s results. Solution of halogen Potassium chloride solution Potassium bromide solution Potassium iodide solution Chlorine Orange colour forms Brown colour forms Bromine No reaction Brown colour forms Iodine No reaction No reaction Give the order of reactivity of the halogens from the results in the table above. Explain how you used the results to show this order of reactivity. Order Explanation (2) (d) Write a balanced ionic equation for the reaction of chlorine with bromide ions in solution. (3) Page 25 of 57

26 (e) Explain the order of reactivity of Group 7 elements. Include information about atomic structure. (2) (Total 0 marks) 4 The elements in Group of the periodic table are metals. The elements in Group are called the alkali metals. Why are they called the alkali metals? (2) (b) Explain the increase in reactivity of elements further down the group. (4) Page 26 of 57

27 (c) Lithium oxide is an ionic compound. Draw a dot and cross diagram to show how lithium and oxygen combine to form lithium oxide. Only show the electrons in the outer shell of each atom. Give the charges on the ions formed. (4) (Total 0 marks) 5 Sulfur is a non-metal. Sulfur burns in the air to produce sulfur dioxide, SO 2 Why is it important that sulfur dioxide is not released into the atmosphere? Tick ( ) one box. Sulfur dioxide causes acid rain. Sulfur dioxide causes global dimming. Sulfur dioxide causes global warming. () (b) Sulfur dioxide dissolves in water. What colour is universal indicator in a solution of sulfur dioxide? Give a reason for your answer. (2) Page 27 of 57

28 (c) Sulfur dioxide is a gas at room temperature. The bonding in sulfur dioxide is covalent. Explain, in terms of its structure and bonding, why sulfur dioxide has a low boiling point. (3) (d) In this question you will be assessed on using good English, organising information clearly and using specialist terms where appropriate. Sulfur dioxide is produced when fossil fuels are burned. It is important that sulfur dioxide is not released into the atmosphere. Three of the methods used to remove sulfur dioxide from gases produced when fossil fuels are burned are: wet gas desulfurisation ( W) dry gas desulfurisation ( D) seawater gas desulfurisation ( S). Information about the three methods is given in the bar chart and in Table and Table 2. Method of removing sulfur dioxide Page 28 of 57

29 Table Method Material used How material is obtained W Calcium carbonate, CaCO 3 Quarrying D Calcium oxide, CaO Thermal decomposition of calcium carbonate: CaCO 3 CaO + CO 2 S Seawater From the sea Table 2 Method W D S What is done with waste material Solid waste is sold for use in buildings. Carbon dioxide is released into the atmosphere. Solid waste is sent to landfill. Liquid waste is returned to the sea. Page 29 of 57

30 Evaluate the three methods of removing sulfur dioxide from waste gases. Compare the three methods and give a justified conclusion. (6) (Total 2 marks) Page 30 of 57

31 6 Use the periodic table and the information in the table below to help you to answer the questions. The table shows part of an early version of the periodic table. Group Group 2 Group 3 Group 4 Group 5 Group 6 Group 7 H Li Be B C N O F Na Mg Al Si P S Cl Hydrogen was placed at the top of Group in the early version of the periodic table. The modern periodic table does not show hydrogen in Group. (i) State one similarity between hydrogen and the elements in Group. () (ii) State one difference between hydrogen and the elements in Group. () (b) Fluorine, chlorine, bromine and iodine are in Group 7, the halogens. The reactivity of the halogens decreases down the group. Bromine reacts with a solution of potassium iodide to produce iodine. Br 2 + 2KI 2KBr + I 2 (i) In the reaction between bromine and potassium iodide, there is a reduction of bromine to bromide ions. In terms of electrons, what is meant by reduction? () (ii) Complete the half equation for the oxidation of iodide ions to iodine molecules. 2I (2) Page 3 of 57

32 (iii) Explain, in terms of electronic structure, why fluorine is the most reactive element in Group 7. (3) (Total 8 marks) 7 Glass is made from silicon dioxide. Velirina/iStock/Thinkstock Silicon dioxide has a very high melting point. Other substances are added to silicon dioxide to make glass. Glass melts at a lower temperature than silicon dioxide. Suggest why. () Page 32 of 57

33 (b) Sodium oxide is one of the substances added to silicon dioxide to make glass. (i) Sodium oxide contains Na + ions and O 2 ions. Give the formula of sodium oxide. () (ii) Sodium oxide is made by heating sodium metal in oxygen gas. Complete the diagram to show the outer electrons in an oxygen molecule (O 2 ). (2) (c) Glass can be coloured using tiny particles of gold. Gold is a metal. Describe the structure of a metal. (3) (Total 7 marks) Page 33 of 57

34 8 Kelp is a seaweed. Kelp can be used in foods and as a renewable energy source. Ethan Daniels/Shutterstock Scientific experiments, on their own, cannot fully answer one of the following questions. Which one? Tick ( ) one box. Questions Tick ( ) How much carbon dioxide is produced when 00 g of kelp is burned? Does kelp give out more heat energy than coal? Will kelp last longer than coal as an energy source? Which fuel, kelp or coal, produces the most ash when burned? () (b) Scientists cannot answer the question should people use kelp instead of coal as an energy source? Give two reasons why. (2) Page 34 of 57

35 (c) Sodium iodide can be produced from kelp. (i) How many electrons are in the outer shell of an iodine atom? () (ii) Sodium iodide contains sodium ions (Na + ) and iodide ions (I ). Describe, as fully as you can, what happens when sodium atoms react with iodine atoms to produce sodium iodide. You may use a diagram in your answer (3) Page 35 of 57

36 (iii) The diagram shows the structure of sodium iodide. Solid sodium iodide does not conduct electricity. Why does sodium iodide solution conduct electricity? () (iv) When sodium iodide solution is electrolysed, iodine is formed at the positive electrode. Complete and balance the half equation for the formation of iodine. I I 2 + e () (v) What is formed at the negative electrode when sodium iodide solution is electrolysed? Explain why. (2) (Total marks) Page 36 of 57

37 9 The picture shows a copper kettle being heated on a camping stove. Copper is a good material for making a kettle because: it has a high melting point it is a very good conductor of heat. Explain why copper, like many other metals, has a high melting point. Your answer should describe the structure and bonding of a metal. (4) Page 37 of 57

38 (b) Aeroplanes contain many miles of electrical wiring made from copper. This adds to the mass of the aeroplane. It has been suggested that the electrical wiring made from copper could be replaced by carbon nanotubes which are less dense than copper. The diagram shows the structure of a carbon nanotube. (i) What does the term nano tell you about the carbon nanotubes? () (ii) Like graphite, each carbon atom in the carbon nanotube is joined to three other carbon atoms. Explain why the carbon nanotube can conduct electricity. (2) (Total 7 marks) Page 38 of 57

39 20 Dmitri Mendeleev was one of the first chemists to classify the elements by arranging them in order of their atomic weights. His periodic table was published in 869. How did Mendeleev know that there must be undiscovered elements and how did he take this into account when he designed his periodic table? (2) (b) By the early 20th century protons and electrons had been discovered. Describe how knowledge of the numbers of protons and electrons in atoms allow chemists to place elements in their correct order and correct group. (3) (c) The transition elements are a block of elements between Groups 2 and 3 of the periodic table. (i) Transition elements have similar properties. Explain why, in terms of electronic structure. (2) Page 39 of 57

40 (ii) There are no transition elements between the Group 2 element magnesium and the Group 3 element aluminium. Give a reason why, in terms of electronic structure. () (Total 8 marks) Page 40 of 57

41 Mark schemes A base (b) forces (c) calcium loses electrons and oxygen gains electrons max 3 for incorrect reference to atom / ion or to oxygen / oxide two electrons are transferred calcium has a 2 + charge oxide has a 2 charge [6] kg (b) all points correct ± ½ small square allow mark if 5 points correct 2 best fit line (c) 5525 dm 3 (d) relative formula mass of TiCl 4 is % Answer given to 3 significant figures = 25.3 % 25.23% with or without working gains 3 marks (e) argon is unreactive water (vapour) would react with sodium allow water (vapour) would react with titanium(iv) chloride Page 4 of 57

42 (f) and air contains oxygen that would react with reactants allow and air contains oxygen that would react with products (titanium conducts electricity) because electrons in the outer shell of the metal atoms are delocalised and so electrons are free to move allow the delocalised electrons in the metal carry electrical charge through the metal through the whole structure [5] 3 mobile phase propanone stationary phase paper (b) any three from: contains chlorophyll a, b and carotene contains Pigment B does not contain pheophytin contains (at least) one unknown substance contains five substances contains a substance that does not dissolve in the solvent 3 (c) (d) both measurements correct solvent front = 9.0 cm and pigment B distance = 5.0 cm R f = 5.0 / 9.0 = 0.56 allow ecf from incorrect measurements (e) origin line drawn in ink so it will run or dissolve in the solvent or split up spots under solvent or solvent above spots / origin line Page 42 of 57

43 so they will mix with solvent or wash off paper or colour the solvent or dissolve in the solvent [3] 4 (i) neutrons this order only electrons protons (ii) box on the left ticked (b) (i) effervescence / bubbling / fizzing / bubbles of gas do not accept just gas alone magnesium gets smaller / disappears allow magnesium dissolves allow gets hotter or steam produced ignore references to magnesium moving and floating / sinking and incorrectly named gases. Page 43 of 57

44 (ii) Marks awarded for this answer will be determined by the Quality of Communication (QC) as well as the standard of the scientific response. Examiners should also refer to the information in the Marking Guidance and apply a best fit approach to the marking. 0 marks No relevant content Level ( 2 marks) There are simple statements of some of the steps in a procedure for obtaining magnesium chloride. Level 2 (3 4 marks) There is a description of a laboratory procedure for obtaining magnesium chloride from dilute hydrochloric acid and magnesium. The answer must include a way of ensuring the hydrochloric acid is fully reacted or a method of obtaining magnesium chloride crystals. Level 3 (5 6 marks) There is a well organised description of a laboratory procedure for obtaining magnesium chloride that can be followed by another person. The answer must include a way of ensuring the hydrochloric acid is fully reacted and a method of obtaining magnesium chloride crystals. examples of the points made in the response: hydrochloric acid in beaker (or similar) add small pieces of magnesium ribbon until magnesium is in excess or until no more effervescence occurs * filter using filter paper and funnel filter excess magnesium pour solution into evaporating basin / dish heat using Bunsen burner leave to crystallise / leave for water to evaporate / boil off water decant solution pat dry (using filter paper). *Student may choose to use a named indicator until it turns a neutral colour, record the number of pieces of magnesium added then repeat without the indicator. 6 [2] 5 (i) protons allow protons or electrons, but do not allow protons and electrons (ii) protons plus / and neutrons Page 44 of 57

45 (b) (because the relative electrical charges are) () for an electron and +() for a proton allow electrons are negative and protons are positive and the number of electrons is equal to the number of protons if no other mark awarded, allow mark for the charges cancel out (c) (the electronic structure of) fluorine is 2,7 and chlorine is 2,8,7 allow diagrams for the first marking point (so fluorine and chlorine are in the same group) because they have the same number of or 7 electrons in their highest energy level or outer shell if no other mark awarded, allow mark for have the same / similar properties (d) S (e) (i) ions (ii) molecules [9] 6 because this lithium atom has 3 protons and 4 neutrons mass number is total of neutrons and protons accept protons and neutrons have a mass of accept number of neutrons = 7-3(protons) ignore mass of electron is negligible (b) grams accept g 2 C allow carbon-2 or C-2 ignore hydrogen or H Page 45 of 57

46 (c) any three from: max 2 if no numbers given numbers if given must be correct both have 8 protons accept same number of protons 8 O has 0 neutrons 6 O has 8 neutrons accept different number of neutrons or 8 O has two more neutrons for mark both have 8 electrons. accept same number of electrons 3 [8] 7 (iron) is a metal accept transition element allow (iron) had different properties (to oxygen and sulfur) ignore electrons (b) so that elements with similar properties could be placed together allow to make the pattern fit ignore undiscovered elements (c) atomic number(s) allow proton number(s) (d) all have one electron in the outer shell (highest energy level) allow same number of electrons in the outer shell (highest energy level) (so they) have similar properties or react in the same way allow specific reactions e.g. with water [5] 8 increase (b) (i) Na + and Br both required Page 46 of 57

47 (ii) (iii) (iv) sodium chloride allow NaCl do not allow sodium chlorine chlorine is more reactive than bromine fluorine allow converse argument allow symbols Cl, Cl 2, Br and Br 2 allow chlorine / it is more reactive do not allow chloride or bromide allow F / F 2. do not allow fluoride. [5] 9 Li and K either order allow lithium and potassium (b) Fe allow iron (c) N and As either order allow nitrogen and arsenic (d) Cu allow copper [4] m (b) / one allow alkali metals (c) R and S because they have the same number of protons allow same atomic number, different mass number Page 47 of 57

48 and a different numbers of neutrons (d) Level 3 (5 6 marks): A relevant and coherent explanation of the trend in reactivity. The response makes logical links between the points raised and considers both the number of energy levels and the distance between the nucleus and the outer energy level. Level 2 (3 4 marks): Statements that are linked to provide a simple explanation of the trend in reactivity using either the number of energy levels or the distance between the nucleus and the outer energy level. Level ( 2 marks): Simple statements made about the halogens or the trend in reactivity. 0 marks: No relevant comment Indicative content Simple statements / descriptions have 7 electrons in the outer shell need to gain an electron form ions with a - charge halogens further down the group are less reactive (or vice versa) halogens further down the group have more shells or energy levels (or vice versa) Linked statements / explanations have 7 electrons in the outer shell so need to gain an electron to have the electronic structure of a noble gas halogens further down the group are less reactive because they have more shells or energy levels (or vice versa) halogens further down the group have more shells or energy levels so less attractive force on the incoming electron (or vice versa) halogens further down the group have more shells or energy levels so more shielding against the incoming electron (or vice versa) outer electrons of halogens further down group are further away from the attractive force of the nucleus (or vice versa) an electron is less easily gained because there are more shells or energy levels (or vice versa) an electron is less easily gained because the outer electrons are further from the attractive force of the nucleus (or vice versa) 6 [] density = mass / volume Page 48 of 57

49 (b) any two from: (c) no forces shown between spheres atoms / molecules / ions are not solid spheres not all the same size. at higher temperatures particles have more kinetic energy (so) the (average) speed of the particles increases (so there are) more frequent collisions with the wall of the container 2 which apply a greater force on wall of container (so pressure rises) [7] 2 most alpha particles went straight through, suggesting lots of empty space a few alpha particles bounced back, suggesting small central nucleus with all the positive charge the plum pudding model does not explain the results because it shows the whole atom as a ball of positive charge with no empty space (b) (c) (d) the figures show that the radius of an atom is times bigger than the nucleus consistent with the nuclear model, which says that the atom has a tiny nucleus at the centre of the atom all hydrogen atoms have just one proton (in the nucleus) some hydrogen atoms also have one neutron protons and neutrons have the same relative mass so mass number of these atoms is 2 neutrons are not attracted or repelled by a positive nucleus so the neutrons would all pass through the foil [] Page 49 of 57

50 3 did not appear because they had not been discovered or they are unreactive or they did not form compounds (b) arranged in order of atomic / proton number elements in the same group have the same number of electrons in the outer shell (c) chlorine>bromine>iodine table shows that chlorine displaces bromine and iodine and bromine displaces iodine (d) Cl 2 (aq) + 2 Br (aq) Br 2 (aq) + 2 Cl (aq) correct formulae correct balancing correct state symbol (e) the further down the group, the halogen becomes less reactive because outer electrons are further from the nucleus so less attractive force on an incoming electron [0] 4 because they form hydroxides that give alkaline solutions (in water) (b) the atoms have more electron shells (as move down the group) so the electron in the outer shell is further away from the nucleus which reduces the attraction to the nucleus so the electron is lost more easily from the atom Page 50 of 57

51 (c) electronic structure of lithium drawn correctly electronic structure of oxygen drawn correctly correct charge on ions (Li + and O 2 ) correct number of each ion (2 lithium, oxygen) [0] 5 Sulfur dioxide causes acid rain. (b) red / orange / yellow do not accept any other colours because sulfur dioxide (when in solution) is an acid (c) (there are) weak forces (of attraction) do not accept any reference to covalent bonds breaking between the molecules do not accept any other particles (these) take little energy to overcome award third mark only if first mark given Page 5 of 57

52 (d) Marks awarded for this answer will be determined by the Quality of Communication (QC) as well as the standard of the scientific response. Examiners should also refer to the information on page 5 and apply a best-fit approach to the marking. 0 marks No relevant content Level ( 2 marks) A relevant comment is made about the data. Level 2 (3 4 marks) Relevant comparisons have been made, and an attempt made at a conclusion. Level 3 (5 6 marks) Relevant, detailed comparisons made and a justified conclusion given. examples of the points made in the response effectiveness W removes the most sulfur dioxide D removes the least sulfur dioxide material used Both W and D use calcium carbonate Calcium carbonate is obtained by quarrying which will create scars on landscape / destroy habitats D requires thermal decomposition, this requires energy D produces carbon dioxide which may cause global warming / climate change S uses sea water, this is readily available / cheap waste materials W product can be sold / is useful W makes carbon dioxide which may cause global warming / climate change D waste fill landfill sites S returned to sea / may pollute sea / easy to dispose of 6 [2] 6 (i) any one from: one electron in the outer shell / energy level form ions with a + charge Page 52 of 57

53 (ii) I 2 must both be on the right hand side of the equation (ii) any one from: hydrogen is a non-metal (at RTP) hydrogen is a gas hydrogen does not react with water hydrogen has only one electron shell / energy level hydrogen can gain an electron or hydrogen can form a negative / hydride / H ion hydrogen forms covalent bonds or shares electrons accept answers in terms of the Group elements (b) (i) (bromine) gains electrons it = bromine do not accept bromide ion gains electrons ignore loss of oxygen + 2e 2I 2e I 2 for 2 marks (iii) fluorine is the smallest atom in Group 7 or has the fewest energy levels in Group 7 or has the smallest distance between outer shell and nucleus the outer shell must be mentioned to score 3 marks fluorine has the least shielding or the greatest attraction between the nucleus and the outer shell therefore fluorine can gain an electron (into the outer shell) more easily [8] Page 53 of 57

54 7 weaker bonds allow (other substances) react with the silicon dioxide or fewer bonds ignore weaker / fewer forces or disruption to lattice do not accept reference to intermolecular forces / bonds (b) (i) Na 2 O do not accept brackets or charges in the formula (ii) electrons can be shown as dots, crosses, e or any combination (c) 2 bonding pairs accept 4 electrons within the overlap 2 lone pairs on each oxygen accept 4 non-bonding electrons on each oxygen lattice / regular pattern / layers / giant structure / close-packed arrangement (of) positive ions or (of) atoms (with) delocalised / free electrons reference to incorrect particles or incorrect bonding or incorrect structure = max 2 [7] 8 Will kelp last longer than coal as an energy source? Page 54 of 57

55 (b) any two from: cannot be determined by experiment allow can t predict how long kelp / coal will last allow more testing needed based on opinion ethical or environmental or economic reason (c) (i) 7 allow could damage ecosystem allow reference to cost 2 (ii) (iii) sodium (atom) loses (electron) and iodine (atom) gains (an electron) electron reference to incorrect bonding or incorrectly named particle = max 2 any or all marks can be obtained from a labelled diagram ignore inner shell electrons if shown (electrostatic) attraction or forms ionic bond(s) ions can move (in the solution) (iv) 2 I I e (v) hydrogen is formed because sodium is more reactive (than hydrogen) [] 9 reference to incorrect bonding or incorrect structure or incorrect particles = max 3 giant structure / lattice ignore many bonds made up of positive ions surrounded by delocalized / free electrons allow positive ions surrounded by a sea of electons Page 55 of 57

56 with strong bonds / attractions allow hard to break for strong so a lot of energy is needed to break these bonds / attractions / forces ignore high temperature ignore heat (b) (i) that they are very small or (ii) -00 nanometres or a few(hundred) atoms accept tiny / really small / a lot smaller / any indication of very small eg. microscopic, smaller than the eye can see ignore incorrect numerical values if very small is given delocalised / free electrons allow sea of electrons one non-bonded electron from each atom accept electron(s) moving through the structure / nanotube allow electron(s) carry / form / pass current / charge [7] 20 if placed consecutively, then elements would be in wrong group / have wrong properties allow some elements didn t fit pattern left gaps (b) (elements placed in) atomic / proton number order (elements in ) same group have same number of outer electrons any one from: number of protons = number of electrons reactions/(chemical) properties depend on the (outer) electrons number of shells gives the period allow number of shells increases down the group Page 56 of 57

57 (c) (i) (transition elements usually) have same / similar number of outer / 4th shell electrons allow 2 electrons in outer shell (because) inner (3rd ) shell / energy level is being filled ignore shells overlap (ii) 2 nd shell / energy level can (only) have maximum of 8 electrons accept no d-orbitals or 2 nd shell / energy level cannot have 8 electrons [8] Page 57 of 57