2021 YIJC Prelim P2 Answer

©YIJC [Turn over YISHUN INNOVA JUNIOR COLLEGE JC 2 PRELIMINARY EXAMINATION Higher 2 CANDIDATE NAME TEACHERS’ COPY CG INDEX NO CHEMISTRY Paper 2 Structured Questions Candidates answer on the Question Paper Additional Materials: Data Booklet 9729/02 30 August 2021 2 hours This document consists of 19 printed pages and 3 blank pages. For Examiner’s Use Paper 1 /30 Paper 2 1 /7 2 /5 3 /7 4 /17 5 /11 6 /22 7 /6 Penalty /75 Paper 3 /80 Paper 4 /55 Overall Percentage (%) READ THESE INSTRUCTIONS FIRST Write your name, class and index number on all the work you hand in. Write in dark blue or black pen on both sides of the paper. You may use an HB pencil for any diagrams or graphs. Do not use staples, paper clips, glue or correction fluid. Answer all questions in the spaces provided on the Question Paper. The use of an approved scientific calculator is expected, where appropriate. A Data Booklet is provided. At the end of the exam ination, fasten all your work securely together. The number of marks is given in brackets [ ] at the end of each question or part question.

2 ©YIJC Answer all the questions in this section in the spaces provided. 1 Use of the Data Booklet is relevant to this question. This question is about period 3 elements. (a) (i) State the electronic configuration of argon. [1] 1s22s22p63s23p6 (ii) Using the Cartesian axes shown in Fig. 1.1, draw a fully labelled diagram of the valence orbitals of argon. Fig 1.1 [1]

3 ©YIJC [Turn over (iii) Two glass vessels B and C are connected by a closed valve as shown in Fig 1.2. Fig. 1.2 B contains argon at 20 C at a pressure of 1 x 10 5 Pa. C has been evacuated and has three times the volume of B. In an experiment, the valve was opened and the temperature of the whole apparatus was raised to 100 C. Calculate the final pressure in the system. Since amount of argon is the same throughout, 𝑃1𝑉1 𝑇1 = 𝑃2𝑉2 𝑇2 1 𝑥 105𝑥 𝑉 20+273 = 𝑃2𝑥 4𝑉 100+273 P2(1172V) = 3.73 x 107V P2 = 31825.9 = 31800 Pa (3 sf) [2] (b) Fig 1. 3 shows the fifth, sixth, seventh, eighth and ninth ionisation energies of another element T in Period 3. Fig.1.3 (i) State and explain which period 3 element has these ionisation energy values. [2] 1000 6000 11000 16000 21000 26000 31000 36000 41000 5 6 7 8 9 ionisation energy/ kJ mol1 electron removed

4 ©YIJC Chlorine as it has a large increase in ionisation energy from the removal of 7th to 8 th electron, indicating that there are 7 valence electron in the outermost shell (OR and the 8th electron is removed from an inner quantum shell). (ii) Element U is directly below element T in the periodic table. Explai