(a) (i) What is represented by... (ii) What is represented by... (2) (b) What is the symbol for lithium?... (1) (Total 3 marks)

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1 1 The diagram shows the structure of a lithium atom. (a) (i) What is represented by... (ii) What is represented by... (b) What is the symbol for lithium?... (Total 3 marks) 2 (a) Balance these chemical equations. (i) H 2 + O 2 H 2 O (ii) Al + O 2 Al 2 O 3 (b) Briefly explain why an unbalanced chemical equation cannot fully describe a reaction (Total 4 marks) 3 Here is a symbol equation, with state symbols, for a chemical reaction between solutions of lead nitrate and potassium chloride. Pb (NO 3 ) 2 (aq) + 2 KCl (aq) 2KNO 3 (aq) + PbCl 2 (s) The equation tells you the formulae of the two products of the reaction. Page 1 of 25

2 (a) What are the names of the two products? (b) What else does the equation tell you about these products? 4 (a) (Total 4 marks) You may find the Data Sheet helpful to complete the word equation. These two gases react as shown in the balanced symbol equation. 2H 2 + O 2 2H 2 O Complete the word equation for this reaction. hydrogen (b) Complete this sentence by crossing out the two words in the box that are wrong. This chemical reaction is much faster if a molecule if a is used. (Total 3 marks) 5 There are millions of different substances that make up our world. All these substances are made from chemical elements. (a) What is an element? Page 2 of 25

3 (b) Many substances are compounds. What is a compound? (Total 3 marks) 6 The diagram represents an atom of an element. (a) Choose one word from the box to complete the label on the diagram. electron neutron nucleus (b) (i) What is the atomic (proton) number of this atom?... (ii) Name the element. Use the periodic table on the Data Sheet to help you answer this question. The name of the element is.... (c) (i) Draw a ring around the mass number of this atom Page 3 of 25

4 (ii) Another atom of this element has a different mass number. Draw a ring around the correct word in the box to complete the sentence. electrons Atoms of the same element with different numbers of neutrons are called isotopes. protons (Total 5 marks) 7 To make crude oil more useful it is separated into different fractions. (a) Complete the gaps in the following sentences. Crude oil is separated into different fractions by a process called Each fraction has a different.... Page 4 of 25

5 (b) Each fraction is a mixture of compounds. Most of these compounds are hydrocarbons, made up of the elements hydrogen and carbon. (i) Explain the difference between a mixture and a compound (ii) Explain the difference between a compound and an element (Total 6 marks) 8 The diagram represents an atom of beryllium. Use a number from the box to complete each sentence (a) The atomic number (proton number) of this atom is. (b) The mass number of this atom is. (Total 2 marks) Page 5 of 25

6 9 Crude oil is a mixture of alkanes from which useful fuel fractions can be obtained. Fraction A hydrocarbon in this fraction Boiling point of alkane in C petroleum gases Propane 42 petrol (gasoline) Octane +126 paraffin (kerosene) Dodecane +216 diesel Eicosane +344 (a) (i) Suggest the lowest temperature to which crude oil needs to be heated to vaporise all of these fuel fractions. Temperature... C (ii) Dodecane boils at +216 C. At what temperature will dodecane gas condense to liquid? Temperature... C (iii) Describe what happens in a fractionating column that allows these fractions to be collected (3) (b) Propane is a fuel because it burns in air releasing heat energy. (i) Complete the balancing of the two chemical equations for propane burning in air. 2C 3 H O 2... CO H 2 O 2C 3 H O 2... CO +... H 2 O Page 6 of 25

7 (ii) The products of the two chemical reactions in (b)(i) are different. Explain why (Total 9 marks) Page 7 of 25

8 10 A student used paper chromatography to identify the pigments in spinach leaves. She used propanone as a solvent. Figure 1 shows the student s results. Figure 1 (a) Name the mobile phase and the stationary phase in the student s experiment. Mobile phase... Stationary phase... (b) What does Figure 1 tell you about the green pigment from spinach? (3) Page 8 of 25

9 (c) Write the equation that links distance moved by solvent, distance moved by solute and R f value. (d) Use Figure 1 to calculate the R f value for pigment B. R f value =... (3) Page 9 of 25

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 13 marks) Page 10 of 25

11 11 The elements in the periodic table are arranged in groups. (a) What is similar about the elements in the same group? Tick one box. Chemical properties Atomic numbers Relative atomic masses (b) Figure 1 shows the arrangement of electrons in an atom. Figure 1 What group of the periodic table is this atom in? Group... Page 11 of 25

12 (c) Why are the elements in Group 0 unreactive? Tick one box. They are all gases at room temperature They all have the same atomic number They are all in the same group of the periodic table They all have a stable arrangement of electrons Page 12 of 25

13 (d) A teacher demonstrates the reaction of some alkali metals with water. Look at Figure 2. Figure 2 The students write what they see. 1. The alkali metals float on water. 2. The alkali metals fizz when they react with water. 3. The universal indicator changes from green to purple. 4. The sodium disappears faster than the lithium. Give a reason for each of the four things that the students see. 1. The alkali metals float on water. Reason The alkali metals fizz when they react with water. Reason The universal indicator changes from green to purple. Reason The sodium disappears faster than the lithium. Reason... (4) (Total 7 marks) Page 13 of 25

14 12 (a) The table gives information about two isotopes of hydrogen, hydrogen-1 and hydrogen-2. Hydrogen-1 Hydrogen-2 Atomic number 1 1 Mass number 1 2 An atom of hydrogen-1 is represented as: Show how an atom of hydrogen-2 is represented. (b) (i) Calculate the relative formula mass (M r ) of water, H 2 O Relative atomic masses: H = 1; O = Relative formula mass (M r ) =... (ii) Simple molecules like water have low boiling points. Explain why, in terms of molecules Page 14 of 25

15 (c) Molecules of heavy water contain two atoms of hydrogen-2 instead of two atoms of hydrogen-1. Explain why a molecule of heavy water has more mass than a normal water molecule. You should refer to the particles in the nucleus of the two different hydrogen atoms in your answer. (Total 6 marks) 13 John Newlands arranged the known elements into a table in order of atomic weight. Figure 1 shows part of Newlands table. Figure 1 Group H Li Be B C N O F Na Mg Al Si P S Cl K Ca (a) What are the names of the elements in Group 5 of Newlands table? Tick one box. Calcium and sulfur Carbon and silicon Chlorine and silver Chromium and tin Page 15 of 25

16 (b) In what order is the modern periodic table arranged? Tick one box. Atomic mass Atomic number Atomic size Atomic weight (c) Give two differences between Group 1 of Newlands table and Group 1 of the periodic table. Page 16 of 25

17 (d) In 1864, atoms were thought to be particles that could not be divided up into smaller particles. By 1898, the electron had been discovered and the plum pudding model of an atom was proposed. Figure 2 shows the plum pudding model of an atom of carbon and the nuclear model of an atom of carbon. Figure 2 Compare the position of the subatomic particles in the plum pudding model with the nuclear model. (4) Page 17 of 25

18 (e) Models are used to show the differences between elements, compounds and mixtures. Which circle shows a model of a mixture? Tick one box. (f) Figure 3 shows a model of carbon dioxide. Figure 3 What does each line between the atoms in Figure 3 represent? Tick one box. Covalent bond Intermolecular force Ionic bond Metallic bond (Total 10 marks) Page 18 of 25

19 14 The diagrams show the electronic structure of four different atoms. Use the Chemistry Data Sheet to help you to answer these questions. (a) Name the two sub-atomic particles in the nucleus of an atom. (b) Why is there no overall electrical charge on each atom? (c) Why is Atom A unreactive? (d) Which two of these atoms have similar chemical properties? Give a reason for your answer. (Total 5 marks) Page 19 of 25

20 15 The figure below shows an atom of boron. (a) When the mass of the boron atom is calculated, the mass of the electrons is ignored. Why is the mass of the electrons ignored? (b) How many electrons are there in the boron atom? (c) What is the electrical charge on the nucleus of the boron atom? Tick one box Page 20 of 25

21 (d) The mass number of boron is 11. Use the figure above to calculate the number of neutrons in the nucleus of the boron atom. Explain how you worked out the answer. Number of neutrons =... Explanation... (3) (e) Phosphorus has a mass number of 31 and has 16 neutrons. What percentage of the mass number of phosphorus is the number of neutrons? Give your answer to two significant figures. Percentage =... (Total 8 marks) Page 21 of 25

22 16 Figure 1 shows the plum pudding model of the atom. This model was used by some scientists after the discovery of electrons in Figure 1 Plum-pudding model In 1911 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 (a) 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 25

23 (b) According to modern measurements: the radius of an atom is about m the radius of an atomic nucleus is about m Show that these values fit with the nuclear model of the atom. (c) In 1931 a scientist discovered that there are hydrogen atoms with mass number 2 as well as hydrogen atoms with mass number 1. 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? (Total 11 marks) Page 23 of 25

24 17 (a) Figure 1 shows an atom of element G. Figure 1 Draw a ring around the correct answer to complete each sentence. (i) Label A shows an electron an ion a nucleus (ii) The particle labelled B is an isotope a molecule a neutron (iii) The mass number of element G is (iv) Use the periodic table to identify element G. Element G is boron carbon sodium Page 24 of 25

25 (b) Figure 2 shows a compound of G and hydrogen. Figure 2 Draw a ring around the correct answer to complete each sentence. (i) The formula of the compound in Figure 2 is GH 3 G 3 H 3HG (ii) The type of bonding shown in Figure 2 is covalent ionic metallic (Total 6 marks) Page 25 of 25