2025 TKGS Chemistry Prelim Paper 2 MS

TANJONG KATONG GIRLS’ SCHOOL PRELIMINARY EXAMINATION SECONDARY FOUR EXPRESS CHEMISTRY CANDIDATE NAME ANSWERS CLASS 4 INDEX NUMBER CHEMISTRY 6092/02 Paper 2 15 August 2025 1 hour 45 minutes Candidates answer on the Question Paper. No Additional Materials are required. READ THESE INSTRUCTIONS FIRST Write your Centre number, index number and name 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. DO NOT WRITE ON ANY BARCODES. Section A Answer all questions. Write your answers in the spaces provided. Section B Answer one question. Write your answers in the spaces provided. The number of marks is given in brackets [ ] at the end of each question or part question. A copy of the Periodic Table is printed on page 24. The use of an approved scientific calculator is expected, where appropriate. For Examiner’s Use Section A Section B Total / 80 This document consists of 24 printed pages.

2 Tanjong Katong Girls’ School Sec 4 Preliminary Examination 2025 Section A Answer all questions. 1 The electron arrangement in the outer shells of five elements, A, B, C, D and E are shown in Fig.1.1. All elements are from Period 3 of the Periodic Table. Fig. 1.1 Use the letters A, B, C, D and E to answer the following questions. Minus [1] from Q1 if they use name of elements. Each letter may be used once, more than once or not at all. (a) Which two elements are most likely to be metals? C and D [1] (b) Which element has an atomic number of 16? A [1] (c) Which element will form double covalent bonds with an oxygen atom? A [1] (d) Which two elements will form an ionic compound with the formula type XY? C and E OR D & A [1] (e) Which element will form an oxide that reacts with both acids and bases? C [1] [Total: 5]

3 Tanjong Katong Girls’ School Sec 4 Preliminary Examination 2025 2 (a) Table 2.1 shows information of atoms. Complete Table 2.1. Table 2.1 atoms number of protons number of neutrons number of electrons K19 39 19 20 19 Cr24 52 24 28 24 [2] [1] for each correct row (b) The strength of interactions between particles determines whether the substance is a solid, liquid or gas at room temperature. Potassium oxide, K2O, is a solid while sulfur trioxide, SO3, is a liquid at room temperature. (i) Explain in terms of structure and bonding, why potassium oxide is a solid while sulfur trioxide is a liquid at room temperature. K2O has a giant ionic structure with strong electrostatic forces o