NJC_2024_H1_Chem_Prelim_P2_QP

1 NJC/H1 Chem Preliminary Examination/02/2024 [Turn over NATIONAL JUNIOR COLLEGE SH2 PRELIMINARY EXAMINATION Higher 1 CANDIDATE NAME SUBJECT CLASS REGISTRATION NUMBER CHEMISTRY Paper 2 Structured Questions Candidates answer on the Question Paper. Additional Materials: Data Booklet 8873/02 17 September 2024 2 hours READ THESE INSTRUCTIONS FIRST Write your name, registration number and subject class on all the work you hand in. Write in dark blue or black pen. You may use a soft pencil for any diagrams, graphs or rough working. Do not use staples, paper clips, glue or correction fluid. The use of an approved scientific calculator is expected, where appropriate. Section A Answer all the questions. Section B Answer one question. 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. A1 /7 A2 /12 A3 /20 A4 /11 A5 /10 Weightage B6 / B7 /20 Paper 1 (33%) /33 Paper 2 /80 Paper 2 (67%) /67 Paper 1 /30 Overall This document consists of 23 printed pages and 1 blank page.

2 NJC/H1 Chem Preliminary Examination/02/2024 Section A Answer all the questions in this section in the spaces provided. 1 The structure of the atom was the subject of much discussion by scientists in the 19th and 20th centuries. The model that is agreed upon today was largely developed by Bohr, Rutherford, Moseley and Chadwick and describes atoms as consisting of smaller particles called protons, neutrons and electrons. (a) (i) Complete the Table 1.1 to show the relative charge, relative mass and behaviour in an electric field of each of these three sub-atomic particles. Table 1.1 proton neutron electron relative charge relative mass Direction of deflection of particle in an electric field [2] (ii) Which particle will be deflected the most in an electric field? ………………………………………………………………………………………… [1] (b) An element has a proton number of 16 and a nucleon number of 33. Draw a detailed diagram to represent the arrangement of protons, neutrons and electrons in an atom of this element. [2]

3 NJC/H1 Chem Preliminary Examination/02/2024 [Turn over (c) The element sulfur has four naturally occurring isotopes as shown in Table 1.2. Table 1.2 isotope relative abundance / % 32S 94.93 33S 0.76 34S 4.29 36S 0.02 Use the relative abundance data to calculate the relative atomic mass of sulfur to 4 significant figures. Show your working. [2] [Total : 7]

4 NJC/H1 Chem Preliminary Examination/02/2024 2 (a) With reference to the Data Booklet, state and explain the trend in the thermal stability of hydrogen halides down the group. ……………………………………………………………………………………………….. ………………………………………………………………………