NJC 2019 H1 Promo Paper 2 (QP)

1 NJC Promotional Examination 8873/02/19 [Turn over NATIONAL JUNIOR COLLEGE SH 1 PROMOTIONAL EXAMINATIONS Higher 1 CANDIDATE NAME SUBJECT CLASS REGISTRATION NUMBER CHEMISTRY Paper 2 Structured Questions Additional Materials: Data Booklet 8873/02 Tues 1 Oct 2019 1 hour 30 min READ THE INSTRUCTIONS FIRST Write your name, subject class and registration number on all the work you hand in. Write in dark blue or black ink on both sides of the paper. You may use a soft pencil for any diagrams or graphs. Do not use paper clips, highlighters, glue or correction fluid. Structured Questions Answer ALL questions on the question paper. The use of an approved calculator is expected where appropriate. A Data Booklet is provided. The number of ma rks is given in brackets [ ] at the end of each question or part question. Appropriate significant figures and units are expected for final numerical answers. For Examiner’s Use 1 /7 2 /4 3 /5 4 /14 5 /7 6 /5 7 /10 8 /8 Penalty s.f. units Total /60 This document consists of 15 printed pages and 1 blank page.

2 NJC Promotional Examination 8873/02/19 [Turn over Answer ALL questions in the space provided. 1 (a) A sample of lead contains four stable isotopes with the following percentage abundances. Isotope Percentage abundance / % 204Pb 1.4 206Pb 24.1 207Pb 22.1 208Pb a For Examiner’s Use (i) Define the term relative atomic mass. ………………………………………………………………………………………………..… …………………………………………………………………………..……………………… [1] (ii) Determine the value of a. Hence calculate the relative atomic mass of lead. Give your answer to two decimal places. [2] (iii) Bismuth is on the right side of lead in the Periodic Table. Predict and explain whether bismuth has a higher or lower first ionisation energy compared to lead. ………………………………………………………………………………………………..… ………………………………………………………………………………………………..… …………………………………………………………………………..……………………… [2]

3 NJC Promotional Examination 8873/02/19 [Turn over (b) When the atomic orbitals from two atoms overlap a chemical bond may result. The p orbitals can overlap to form sigma (σ) or pi (π) bonds. When two atoms overlap the z-axis is used to define the internuclear axis. For Examiner’s Use (i) On the diagram below draw two p orbitals (one orbital on each atom) that could overlap to produce a sigma (σ) bond. atom 1 atom 2 [1] (ii) On the diagram below draw two p or