Q1. The electronic structure of the atoms of five elements are shown in the figure below.

Transcription

1 Q. The electronic structure of the atoms of five elements are shown in the figure below. The letters are not the symbols of the elements. Choose the element to answer the question. Each element can be used once, more than once or not at all. Use the periodic table to help you. (a) Which element is hydrogen? Tick one box. A B C D E () (b) Which element is a halogen? Tick one box. A B C D E () (c) Which element is a metal in the same group of the periodic table as element A? Tick one box. A B C D E () (d) Which element exists as single atoms? Tick one box. A B C D E () Page of 23

2 (e) There are two isotopes of element A. Information about the two isotopes is shown in the table below. Mass number of the isotope 6 7 Percentage abundance Use the information in the table above above to calculate the relative atomic mass of element A. Give your answer to 2 decimal places Relative atomic mass =... (4) (Total 8 marks) Q2. This question is about metals. (a) Which unreactive metal is found in the Earth as the metal itself? Tick ( ) one box. aluminium gold magnesium () (b) Complete the sentence. Aluminium is an element because aluminium is made of only one type of.... () Page 2 of 23

3 (c) Figure shows the electronic structure of an aluminium atom. (i) Use the correct words from the box to complete the sentence. electrons ions protons neutrons shells The nucleus of an aluminium atom contains... and.... (2) Complete the sentence. In the periodic table, aluminium is in Group.... () (d) Aluminium is used for kitchen foil. Figure 2 shows a symbol on a box of kitchen foil. The symbol means that aluminium can be recycled. It does not show the correct chemical symbol for aluminium. (i) What is the correct chemical symbol for aluminium?.... () Page 3 of 23

4 Give two reasons why aluminium should be recycled (2) (e) Aluminium has a low density, conducts electricity and is resistant to corrosion. Which one of these properties makes aluminium suitable to use as kitchen foil? Give a reason for your answer (2) (Total 0 marks) Q3. An atom of aluminium has the symbol (a) Give the number of protons, neutrons and electrons in this atom of aluminium. Number of protons... Number of neutrons... Number of electrons... (3) (b) Why is aluminium positioned in Group 3 of the periodic table? () Page 4 of 23

5 (c) In the periodic table, the transition elements and Group elements are metals. Some of the properties of two transition elements and two Group elements are shown in the table below. Transition elements Group elements Chromium Iron Sodium Caesium Melting point in C Formula of oxides CrO FeO Na 2 O Cs 2 O Cr 2 O 3 Fe 2 O 3 CrO 2 Fe 3 O 4 CrO 3 Use your own knowledge and the data in the table above to compare the chemical and physical properties of transition elements and Group elements (6) (Total 0 marks) Q4. This question is about atomic structure and elements. (a) Complete the sentences. (i) The atomic number of an atom is the number of... () The mass number of an atom is the number of () Page 5 of 23

6 (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 6 of 23

7 (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.... () Compounds formed from only non-metals consist of particles called.... () (Total 9 marks) Page 7 of 23

8 Q5. There are eight elements in the second row (lithium to neon) of the periodic table. (a) Figure shows a lithium atom. (i) What is the mass number of the lithium atom in Figure? Tick ( ) one box () What is the charge of an electron? Tick ( ) one box. 0 + () (iii) Protons are in the nucleus. Which other sub-atomic particles are in the nucleus? Tick ( ) one box. ions molecules neutrons () Page 8 of 23

9 (b) What is always different for atoms of different elements? Tick ( ) one box. number of neutrons number of protons number of shells () (c) Figure 2 shows the electron arrangements of three different atoms, X, Y and Z. These atoms are from elements in the second row (lithium to neon) of the periodic table. Which atom is from an element in Group 3 of the periodic table? Tick ( ) one box. Atom X Atom Y Atom Z () (d) Figure 3 shows the electron arrangement of a different atom from an element in the second row of the periodic table. (i) Give the chemical symbol of this element. () Page 9 of 23

10 Why is this element unreactive? () (Total 7 marks) Q6. There are eight elements in the second row (lithium to neon) of the periodic table. (a) Figure shows an atom with two energy levels (shells). (i) Complete Figure to show the electronic structure of a boron atom. () What does the central part labelled Z represent in Figure?... () (iii) Name the sub-atomic particles in part Z of a boron atom. Give the relative charges of these sub-atomic particles. (3) Page 0 of 23

11 (b) The electronic structure of a neon atom shown in Figure 2 is not correct. Explain what is wrong with the electronic structure shown in Figure (3) (Total 8 marks) Q7. This question is about atoms, molecules and nanoparticles. (a) Different atoms have different numbers of sub-atomic particles. (i) An oxygen atom can be represented as O Explain why the mass number of this atom is 6. You should refer to the numbers of sub-atomic particles in the nucleus of the atom. (2) Page of 23

12 Explain why C and C are isotopes of carbon. You should refer to the numbers of sub-atomic particles in the nucleus of each isotope. (3) (b) Hydrogen atoms and oxygen atoms chemically combine to produce water molecules. (i) Complete the figure below to show the arrangement of the outer shell electrons of the hydrogen and oxygen atoms in a molecule of water. Use dots ( ) or crosses ( ) to represent the electrons. (2) Name the type of bonding in a molecule of water.... () (iii) Why does pure water not conduct electricity? () (c) Nanoparticles of cobalt oxide can be used as catalysts in the production of hydrogen from water. (i) How does the size of a nanoparticle compare with the size of an atom? () Page 2 of 23

13 Suggest one reason why g of cobalt oxide nanoparticles is a better catalyst than g of cobalt oxide powder. () (Total marks) Q8. This question is about fluorine. (a) Figure shows the arrangement of electrons in a fluorine atom. (i) In which group of the periodic table is fluorine? Group... () Complete the table below to show the particles in an atom and their relative masses. Name of particle Relative mass Proton Neutron Very small (2) (iii) Use the correct answer from the box to complete the sentence. alkalis alloys isotopes Atoms of fluorine with different numbers of neutrons are called.... () (b) Sodium reacts with fluorine to produce sodium fluoride. (i) Complete the word equation for this reaction. sodium () Page 3 of 23

14 Complete the sentence. Substances in which atoms of two or more different elements are chemically combined are called.... () (iii) The relative formula mass (M r ) of sodium fluoride is 42. Use the correct answer from the box to complete the sentence. ion mole molecule The relative formula mass (M r ), in grams, of sodium fluoride is one... of the substance. () (iv) Figure 2 shows what happens to the electrons in the outer shells when a sodium atom reacts with a fluorine atom. The dots ( ) and crosses ( ) represent electrons. Use Figure 2 to help you answer this question. Describe, as fully as you can, what happens when sodium reacts with fluorine to produce sodium fluoride. (4) Page 4 of 23

15 (v) Sodium fluoride is an ionic substance. What are two properties of ionic substances? Tick ( ) two boxes. Dissolve in water Gas at room temperature High melting point Low boiling point (2) (Total 3 marks) Page 5 of 23

16 M. (a) B (b) (c) (d) (e) D E C and allow 6.08 with no working shown for 4 marks [8] M2. (a) gold (b) atom (s) (c) (i) protons any order allow proton neutrons allow neutron 3 / three (d) (i) Al ignore any numbers / charges Page 6 of 23

17 any two from: limited resource expensive in terms of energy / mining effects on the environment, such as, landfill, atmospheric pollution, quarrying allow uses a lot of energy to extract. 2 (e) resistant to corrosion does not react (with water or food) allow one mark for low density with a suitable reason given [0] M3. (a) 3 (protons) The answers must be in the correct order. if no other marks awarded, award mark if number of protons and electrons are equal 4 (neutrons) 3 (electrons) (b) has three electrons in outer energy level / shell allow electronic structure is Page 7 of 23

18 (c) Level 3 (5 6 marks): A detailed and coherent comparison is given, which demonstrates a broad knowledge and understanding of the key scientific ideas. The response makes logical links between the points raised and uses sufficient examples to support these links. Level 2 (3 4 marks): A description is given which demonstrates a reasonable knowledge and understanding of the key scientific ideas. Comparisons are made but may not be fully articulated and / or precise. Level ( 2 marks): Simple statements are made which demonstrate a basic knowledge of some of the relevant ideas. The response may fail to make comparisons between the points raised. 0 marks: No relevant content. Indicative content Physical Transition elements high melting points high densities strong hard Group low melting points low densities soft Chemical Transition elements low reactivity / react slowly (with water or oxygen) used as catalysts ions with different charges coloured compounds Group very reactive / react (quickly) with water / non-metals not used as catalysts white / colourless compounds only forms a + ion 6 [0] M4. (a) (i) protons allow protons or electrons, but do not allow protons and electrons protons plus / and neutrons (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 Page 8 of 23

19 (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 molecules [9] M5. (a) (i) 7 (iii) neutrons (b) (c) number of protons atom Y (d) (i) Ne allow neon has a full outer shell allow in Group 0 allow a noble gas or full outer energy level allow the shells are full or has 8 electrons in its outer shell ignore in Group 8 [7] Page 9 of 23

20 M6. (a) (i) electronic structure 2,3 drawn allow any representation of electrons, such as, dots, crosses, or numbers (2,3) nucleus (iii) protons and neutrons do not allow electrons in nucleus (relative charge of proton) + allow positive (relative charge of neutron) 0 allow no charge/neutral ignore number of particles (b) too many electrons in the first energy level or inner shell allow inner shell can only have a maximum of 2 electrons too few electrons in the second energy level or outer shell allow neon has 8 electrons in its outer shell or neon does not have electron in its outer shell allow neon has a stable arrangement of electrons or a full outer shell neon does not have 9 electrons or neon has 0 electrons allow one electron missing allow fluorine has 9 electrons ignore second shell can hold (maximum) 8 electrons or 2,8,8 rule or is a noble gas or in Group 0 max 2 marks if the wrong particle, such as atoms instead of electrons if no other mark awarded allow mark for the electronic structure of neon is 2,8 [8] M7. (a) (i) (mass number = 6) because there are 8 protons and 8 neutrons (in the nucleus) accept mass number is total number of protons and neutrons for mark 2 same number of protons or both have 6 protons accept same atomic number Page 20 of 23

21 2 C has 6 neutrons 4 C has 8 neutrons (b) (i) 2 bonding pairs accept different number of neutrons for mark numbers, if given, must be correct incorrect reference to electrons = max 2 marks additional unbonded electrons negates this mark 4 unbonded electrons around oxygen accept dot, cross or e or or any combination (iii) covalent any one from: no delocalised / free electrons ignore mobile electrons no overall electric charge accept no charge (carriers) no ions do not accept any implications of the presence of ions (c) (i) larger accept the size of a few hundred atoms accept atoms are smaller (than nanoparticles) allow up to 000 atoms) (nanoparticles have) large(r) surface area [] M8. (a) (i) 7 / seven do not accept Electron (iii) isotopes (b) (i) (sodium + ) fluorine sodium fluoride compounds Page 2 of 23

22 (iii) mole (iv) sodium (atom) loses fluorine (atom) gains one electron ions formed allow sodium forms positive (ion) or fluorine forms negative (ion) allow form ionic bond allow to gain a full outer shell of electrons allow forms noble gas structure max 3 if reference to incorrect particle / bonding (v) Dissolve in water High melting point [3] Page 22 of 23

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