2025 YIJC H1 Chem Prelim P1 Solutions (for exchange)

©YIJC [Turn over YISHUN INNOVA JUNIOR COLLEGE JC 2 PRELIMINARY EXAMINATION Higher 1 CANDIDATE NAME SUGGESTED ANSWERS CG H1 GROUP 1 / 2 / 3 CHEMISTRY Paper 1 Additional Materials: Multiple Choice Answer Sheet Data Booklet 8873 /01 XX September 2025 1 hour READ THESE INSTRUCTIONS FIRST This document consists of 19 printed pages. Write in soft pencil. Do not use staples, paper clips, glue or correction fluid. Write your name and class in the spaces at the top of this page and 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 and 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.

©YIJC [Turn over 2 1 The table below contains incomplete information about three ions, E, F and G, which are isoelectronic (same number of electrons). The atoms of F and G are isotopes. ion mass number atomic number number of neutrons number of electrons charge E 55 25 y F 56 26 G x 31 3+ What are the possible values of x and y? x y A 56 2+ B 56 3+ C 57 2+ D 57 3+ Answer: C ion Mass number Atomic number Number of neutrons Number of electrons charge X 55 25 30 23 2+ Y 56 26 30 23 3+ Z 57 26 31 23 3+

©YIJC [Turn over 3 2 In two separate experiments, a beam of protons and a beam of electrons, travelling at the same velocity, is passed through an electric field as shown. Which set of observations is correct? A The two beams are deflected in opposite directions. The electron beam is deflected the most. B The two beams are deflected in opposite directions. The proton beam is deflected the most. C The two beams are deflected in the same direction. The electron beam is deflected the most. D The two beams are deflected in the same direction. The proton beam is deflected the most. Answer: A Protons are positively charged and hence are deflected towards the negative plate. Electrons are negatively charged and hence are deflected towards the positive plate. As electrons are lighter than protons, electrons are deflected more than protons. 3 Use of the Data Booklet is relevant to this question. Which species has three unpaired electrons? A Al B Ti3+ C Zn2+ D Cr3+ Answer: D Al :