Name: Atomic Structure. Class: Higher paper revision questions. Date: 32 minutes. Time: 32 marks. Marks: Comments: Page 1 of 12

Transcription

1 Atomic Structure Higher paper revision questions Name: Class: Date: Time: 32 minutes Marks: 32 marks Comments: Page of 2

2 Rock salt is a mixture of sand and salt. Salt dissolves in water. Sand does not dissolve in water. Some students separated rock salt. This is the method used.. Place the rock salt in a beaker. 2. Add 00 cm 3 of cold water. 3. Allow the sand to settle to the bottom of the beaker. 4. Carefully pour the salty water into an evaporating dish. 5. Heat the contents of the evaporating dish with a Bunsen burner until salt crystals start to form. (a) Suggest one improvement to step 2 to make sure all the salt is dissolved in the water. () The salty water in step 4 still contained very small grains of sand. Suggest one improvement to step 4 to remove all the sand. () (c) Suggest one safety precaution the students should take in step 5. () Page 2 of 2

3 (d) Another student removed water from salty water using the apparatus in the figure below. Describe how this technique works by referring to the processes at A and B. (2) (e) What is the reading on the thermometer during this process?... C () (Total 6 marks) 2 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. () (ii) What does the central part labelled Z represent in Figure?... () Page 3 of 2

4 (iii) Name the sub-atomic particles in part Z of a boron atom. Give the relative charges of these sub-atomic particles (3) 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 2. (3) (Total 8 marks) 3 This question is about atomic structure and elements. (a) Complete the sentences. (i) The atomic number of an atom is the number of... () (ii) The mass number of an atom is the number of () Page 4 of 2

5 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 5 of 2

6 (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 6 of 2

7 4 The diagram shows an electric light bulb. When electricity is passed through the tungsten filament it gets very hot and gives out light. (a) What reaction would take place if the hot tungsten was surrounded by air? () State why argon is used in the light bulb. Explain your answer in terms of the electronic structure of an argon atom. (3) (Total 4 marks) 5 (a) The electronic structure of a sodium atom can be written 2,8,. Write the electronic structure of a potassium atom in the same way. () Page 7 of 2

8 The electronic structure of a sodium atom can also be represented as in the diagram below. (i) Draw a similar diagram for a fluorine atom. (ii) Draw similar diagrams to show the electronic structure of the particles in sodium fluoride. (4) (Total 5 marks) Page 8 of 2

9 Mark schemes (a) any one from: heat stir filter accept use a centrifuge accept leave longer (to settle) (c) any one from: (d) wear safety spectacles wear an apron evaporation at A condensation at B (e) 00 [6] 2 (a) (i) electronic structure 2,3 drawn allow any representation of electrons, such as, dots, crosses, or numbers (2,3) (ii) (iii) nucleus 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 too many electrons in the first energy level or inner shell allow inner shell can only have a maximum of 2 electrons Page 9 of 2

10 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] 3 (a) (i) protons allow protons or electrons, but do not allow protons and electrons (ii) protons plus / and neutrons (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 Page 0 of 2

11 (d) S (e) (i) ions (ii) molecules [9] 4 (a) react with oxygen / oxidise / burn in oxygen / burning / combustion or tungsten to tungsten oxide or makes an oxide key idea is oxidation ignore breaking ignore fire / flames / exothermic ignore react with air it is (very) unreactive / not reactive / inert / does not react with tungsten or it is a noble gas or it is in group 0 or 8 or 8 do not accept unreactive / inert metal or argon is not very reactive full outer shell (of electrons) / 8 electrons in outer shell does not need to gain / lose / swap / transfer / share electrons or does not need to form bonds does not bond ionically / covalently [4] 5 (a) 2, 8, 8, for mark for mark Ignore symbol in middle but structure must be drawn NOT 2,7 Page of 2

12 If covalent; can score mark for changes but not for diagram Arrow showing electron transfer from metal atom to non-metal atom = 2 marks If the ions are not identified then cannot score mark for changes 4 [5] Page 2 of 2