QUESTIONSHEETS PERIODIC TABLE I MELTING POINTS AND BOILING POINTS IONISATION ENERGIES AND ELECTRON AFFINITIES ELECTRONEGATIVITIES AND BONDING

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1 CHEMISTRY QUESTIONSHEETS AS Level AS TOPIC 9 PERIODIC TABLE I Questionsheet 1 Questionsheet 2 Questionsheet 3 Questionsheet 4 Questionsheet 5 Questionsheet 6 Questionsheet 7 Questionsheet 8 Questionsheet 9 Questionsheet 10 BASIC CONCEPTS ATOMIC AND IONIC RADII STRUCTURES MELTING POINTS AND BOILING POINTS ELECTRICAL CONDUCTIVITY IONISATION ENERGIES AND ELECTRON AFFINITIES ELECTRONEGATIVITIES AND BONDING OXIDATION NUMBERS TEST QUESTION I TEST QUESTION II 18 marks 17 marks 13 marks 14 marks 16 marks 15 marks 15 marks 15 marks 16 marks 16 marks Authors Trevor Birt Donald E Caddy Andrew Jones Adrian Bond Editors John Brockington Stuart Barker John Brockington Kevin Frobisher Andy Shepherd Stuart Barker Curriculum Press Licence Agreement: Paper copies of the A-Level Chemistry Questionsheets may be copied free of charge by teaching staff or students for use within their school, provided the Photocopy Masters have been purchased by their school. No part of these Questionsheets may be reproduced or transmitted, in any other form or by any other means, without the prior permission of the publisher. All rights are reserved. This license agreement is covered by the laws of England and Wales Curriculum Press March Curriculum P ress Curriculum Press Bank House 105 King Street Wellington Shropshire TF1 1NU

2 TOPIC 9 Questionsheet 1 BASIC CONCEPTS The Periodic Table arranges the different elements in a pattern according to the structure of their atoms and the way in which they behave. a) In what order are the elements arranged in the Periodic Table? What name is given to the vertical columns? (iii) What name is given to the horizontal rows? b) What names are given to the following groups in the Periodic Table? Group 1... [1] Group 2... [1] (iii) Group 7... [1] (iv) Group 0... [1] c) What name is given to the block of elements found between Groups 2 and 3? d) What is the connection between the electronic configuration of an element and: the group in which the element is found? the period in which the element is found? e) Periodicity is the study of the patterns of properties of the elements found in the Periodic Table. State the general trends in the variation of the following properties of the elements Na Ar across Period 3. In each case state the major factor which influences this change. Atomic radius Trend... Cause... [2] Melting point Trends... Causes [4] (iii) First ionisation energy Trend... Cause... [2] TOTAL / 18

3 TOPIC 9 Questionsheet 2 ATOMIC AND IONIC RADII a) State and explain the following trends. The variation of atomic radius across a period of the Periodic Table. The variation of the charge on cations of the elements of Groups 1, 2 and 3 of the Periodic Table. b) What is meant by the polarising power of a cation? Explain how the polarising power of cations varies across a period of the Periodic Table. c) Are the radii of Period 3 atoms (Na-Ar) greater or less than those of the corresponding Period 2 atoms (Li-Ne)? Explain your answer. d) Explain the following facts. The radius of a fluoride ion is greater than that of a sodium ion, even though they both have the same electronic configuration. Cations (e.g. Na + ) are smaller than their parent atoms, while anions (e.g. Cl - ) are larger than their parent atoms.... [4] TOTAL / 17

4 a) Complete the following table. TOPIC 9 Questionsheet 3 STRUCTURES Element Na Mg Al Si P S Cl Nature of Bonding Type of Structure [8] b) From Period 2, name the elements that correspond to these descriptions: Description Element Can exist in a giant covalent structure where each atom is tetrahedrally bonded to four others Simple molecules with six lone pairs (iii) Simple molecules containing triple bonds (iv) A gas with discrete atoms (v) A metallic structure containing +1 ions [5] TOTAL / 13

5 TOPIC 9 Questionsheet 4 MELTING POINTS AND BOILING POINTS a) The melting points of the elements of Period 3 are as follows: Element Na Mg Al Si P(white) S(α) Cl Ar m.p./ 0 C Explain the following. The increase in melting points from Na Al. The very high melting point of silicon. (iii) The variation in melting points from P-Ar.... [4] b) What tend in boiling points would you expect on progressing from sodium to aluminium? How do you explain the fact that, although the boiling point of silicon is very high ( C), the percentage increase in temperature from melting point to boiling point is less for silicon than for most of the other elements? (iii) Why is the boiling point of argon ( C) only slightly higher than its melting point? TOTAL / 14

6 TOPIC 9 Questionsheet 5 ELECTRICAL CONDUCTIVITY a) State and describe the type of bonding present in Na, Mg and Al. Type of bonding... [1] Description [2] Explain why the electrical conductivity of these elements is relatively high. (iii) Why does electrical conductivity increase from Na to Mg to Al? b) The electrical conductivities (in units of 10 8 S m -1 ) of some elements in Groups 1, 2, 3 and 4 are shown below. Group 1 Group 2 Group 3 Group 4 Li B Na Mg Al Si Ge Sn Use the value for boron to state and explain the type of bonding present in this element. Type of bonding... [1] Explanation [2] What do the values for the group 4 elements tell you about the change in element type down the group? Change... [1] Reasoning [2] (iii) What do the values of aluminium and silicon suggest about the change in structure in Period 3 at this point? Change... [1] Reasoning... [1] TOTAL / 16

7 TOPIC 9 Questionsheet 6 IONISATION ENERGIES & ELECTRON AFFINITIES a) One of the figures labelled I IV shows the variation of first ionisation energies across Period 2 of the Periodic Table. Figure I Figure II Li Be B C N O F Ne Li Be B C N O F Ne Figure III Figure IV Li Be B C N O F Ne Li Be B C N O F Ne Which of these figures is the correct one?... [1] Explain why you have chosen this figure, referring in your answer to both the general trend and any irregularities. General trend [3] Irregularities [4] TOTAL (Continued...) /

8 TOPIC 9 Questionsheet 6 Continued IONISATION ENERGIES & ELECTRON AFFINITIES b) On the figure you have chosen for a), sketch the corresponding graph you would expect for the elements of Period 3 (Na-Ar). [1] What are the reasons for the principal difference between the two graphs? c) Which out of Na Mg Al would have the largest second ionization energy? Explain your reasoning TOTAL / 15

9 TOPIC 9 Questionsheet 7 ELECTRONEGATIVITIES AND BONDING a) Define the electronegativity of an element. State and explain how the electronegativities of elements vary across a period of the Periodic Table.... [4] b) State how the elements of Period 3 (Na Ar) vary with regard to their tendency to undergo ionic bonding and covalent bonding. c) Explain briefly how the electronegativities of two elements whose atoms form an interatomic chemical bond affect the type of bond that is formed. d) Predict whether the bond character in PCl 3 is more or less ionic than that in NCl 3, and explain your suggestion by referring to the trend in electronegativity values down a group of the Periodic Table. TOTAL / 15

10 TOPIC 9 Questionsheet 8 OXIDATION NUMBERS a) In which groups of the Periodic Table do the elements normally display only a single oxidation number in their chlorides, oxides and hydrides? b) State the two principal oxidation numbers of phosphorus in its compounds and write a chemical formula for each of two oxides and two chlorides of phosphorus.... [5] c) For the compound sulfur hexafluoride (SF 6 ): F F F S F F F What is the oxidation number of sulfur?...[1] Explain how such an oxidation number can be achieved.... [4] (iii) Write the chemical formulae of three other sulfur-containing compounds in each of which sulfur displays different oxidation numbers. Show the oxidation numbers clearly. TOTAL / 15

11 TOPIC 9 Questionsheet 9 TEST QUESTION I The elements in Period 2 follow similar patterns of those in Period 3. Use your knowledge of trends in properties across Period 3 when answering this Questionsheet. a) The atomic numbers and atomic radii of the elements in Period 2 are given below. Element Li Be B C N O F Atomic number Atomic radius / nm On the graph paper below, plot a suitable graph to estimate the atomic radius of carbon. Atomic radius =... nm [5] Explain the decrease in atomic radii across the period. TOTAL (Continued...) / 15

12 TOPIC 9 Questionsheet 9 Continued TEST QUESTION I b) In what respect do the ionic radii of the elements Li to B: resemble the atomic radii for Li to B? differ from the atomic radii for Li to B? c) The first ionisation energies of selected Period 2 elements are shown below. Element B C N Ionisation energy / kj mol Using the data in the table above, predict the first ionisation energy of oxygen if this trend were continued. The actual first ionisation energy of oxygen is 1314 kj mol -1. Explain the difference between this value and your predicted value. d) The boiling point of a liquid may be defined as the temperature at which its saturated vapour pressure equals atmospheric pressure. Predict how the boiling points of the elements lithium and beryllium will differ. Explain your answer. Difference... Explanation... TOTAL / 16

13 TOPIC 9 Questionsheet 10 TEST QUESTION II The diagram below represents a section of the Periodic Table in which symbols have been replaced by letters. A B C Use this diagram to answer the following questions. a) Write down the letter of the element: with the highest proton number.... [1] found in Group [1] (iii) which is a halogen.... [1] b) Which one of the elements A, B and C has the highest electron affinity? Explain your answer. Element... Explanation... c) State and explain which of the elements A F has: the highest melting point. Element... Explanation [3] the highest electrical conductivity. Element... Explanation [3] d) Element D reacts with element E to give compounds of formulae DE 3 and DE 5. Deduce the oxidation number of D in each of these compounds. Oxidation no. in DE 3... Oxidation no. in DE 5... [2] Use your answer to part d) to predict the formulae of any oxides formed by element D. TOTAL / 16