2025 H1 Chem JC2 Prelim P1 (Q & A) worked solutions_JPJC

© Jurong Pioneer Junior College [Turn over NAME CLASS JURONG PIONEER JUNIOR COLLEGE JC2 PRELIMINARY EXAMINATION 2025 CHEMISTRY 8873/01 Higher 1 Paper 1 Multiple Choice Questions 18 September 2025 1 hour Candidates answer on the Question paper. Additional Materials: Multiple Choice Answer Sheet Data Booklet READ THESE INSTRUCTIONS FIRST Write in soft pencil. Do not use staples, paper clips, glue or correction fluid. Write your name, class and exam index number on the Answer Sheet in the spaces provided unless this has been done for you. There are thirty questions on this paper. Answer all questions. For each question there are four possible answers A, B, C or D. Choose the one you consider correct and record your choice in soft pencil on the separate Answer Sheet. Read the instructions on the Answer Sheet very carefully. Each correct answer will score one mark. A mark will not be deducted for a wrong answer. Any rough working should be done in this booklet. The use of an approved scientific calculator is expected, where appropriate. This document consists of 14 printed pages and 0 blank page.

2 © Jurong Pioneer Junior College 8873/01/J2 PRELIMINARY EXAMINATION /2025 1 Use of Data Booklet is relevant to this question. The atoms X and Y have the electronic configurations shown below. X, 1s2 2s2 2p6 3s2 3p6 4s2 ; Y, 1s2 2s2 2p5 Which compound are they likely to form? A X2Y B XY C XY2 D XY4 1 Answer C X, 1s2 2s2 2p6 3s2 3p6 4s2  has 2 valence electrons, Group 2 element (Ca); tendency to lose 2 electrons to give Ca2+ Y, 1s2 2s2 2p5  has 7 valence electrons, group 17 element (F); tendency to accept 1 electron to form F− Hence will form CaF2 which is XY2 2 The trend of first ionisation energy for 10 consecutive elements , in Period 2 and 3, is given below. Which of the following statement is correct? A Element E and N belong to the same group. B L has a giant covalent structure. C The oxide of J is amphoteric. D The chloride of I is insoluble in water. E F G H I J K L M N proton number first ionisation energy

3 © Jurong Pioneer Junior College 8873/01/J2 PRELIMINARY EXAMINATION /2025 [Turn over 2 Answer B The largest drop in first ionisation energy is between H and I. This indicates H is from 2 period 2 and I is from period 3. H is in group 18 and I is in group 1. Hence, E, nitrogen, and M, phosphorous, belong to the same group, group 15. L is in group 14, silicon, and has a giant covalent structure. The oxide of J, magnesium oxide, is a basic oxide. The chloride of I, sodium chloride, is soluble in water. 3 In which pair of molecules are both non–polar? 1 BeH2 and SO3 2 AlCl3 and CH4 3 PCl5 And SCl6 A 1, 2 and 3 B 1 and 2 only C 2 and 3 only D 1 only 3 Answer A 1 BeH2 is linear. SO3 is trigonal planar. Both