NYJC Prelim H2 Chem 9729 P2

[Turn Over NANYANG JUNIOR COLLEGE JC 2 PRELIMINARY EXAMINATION Higher 2 CANDIDATE NAME CLASS TUTOR’S NAME CHEMISTRY 9729/02 Paper 2 Structured Questions September 2025 2 hours Candidates answer on the Question Paper. Additional Materials: Data Booklet READ THESE INSTRUCTIONS FIRST Write your name and class on all the work you hand in. Write in dark blue or black pen. You may use an HB pencil for any diagrams or graphs. Do not use staples, paper clips, glue or correction fluid. Answer all questions in the spaces provided on the Question Paper. If additional space is required, you should use the pages at the end of this booklet. The question number must be clearly shown. The use of an approved scientific calculator is expected, where appropriate. A Data Booklet is provided. At the end of the examination, fasten all your work securely together. The number of marks is given in brackets [ ] at the end of each question or part question. For Examiner’s Use 1 / 9 2 / 12 3 / 8 4 / 21 5 / 25 Total / 75 This document consists of 19 printed pages. H

2 H2 Chemistry 9729/02 NYJC J2/2025 Prelim Answer all the questions in the spaces provided. 1 (a) Fig. 1.1 below can be used to plot the first ionisation energy of the elements from proton number 12 to 20. Six of these elements have been plotted already. Fig. 1.1 (i) Estimate and plot, on Fig. 1.1 above, the first ionisation energies of elements with proton numbers 13, 16 and 20. [1] (ii) Explain the general increase in first ionisation energy across elements with proton numbers 12 to 18. …………………………………………………………………………………………………... …………………………………………………………………………………………………... …………………………………………………………………………………………………... ………………………………………………………………………………………………...[2] (iii) Write the electronic configurations of the elements with proton numbers 15 and 16, and hence, explain the trend in their first ionisation energies. …………………………………………………………………………………………………... …………………………………………………………………………………………………... …………………………………………………………………………………………………... ………………………………………………………………………………………………...[2]

3 H2 Chemistry 9729/02 NYJC J2/2025 Prelim [Turn Over (b) Electric cables used in fire alarm systems have copper wire surrounded by magnesium oxide, which acts as insulator. (i) In terms of structure and bonding, explain why copper can conduct electricity. Draw a labelled diagram to illustrate your answer. …………………………………………………………………………………………………... …………………………………………………………………………………………………... ………………………………………………………………………………………………...[2] (ii) Suggest, in terms of structure and bonding, why magnesium oxide is a better insulator than sodium oxide. …………