From Atoms to Materials

18. The molecules of two hydrocarbons are shown below. Y has a larger molecular size than X . hydrocarbon X hydrocarbon Y Which of the following statements is correct? A. X is more viscous than Y . B. X has a higher boiling point that Y . C. X is more volatile than Y . D. The colour of X is darker than Y . 19. Which of the following materials is the most malleable? A. Silicon B. Perspex C. Sulphur D. Silver 20. In Hong Kong, a mandatory fee of $0.5 is now imposed on shoppers for each plastic bag take. Which of the ‘4Rs’ principles does this law encourage people to follow? A. Reduce B. Reuse C. Recycle D. Replace Short Question 21. The nuclei of three atoms x , y and z are shown below. atom x atom y atom z n = 10 p = 10 n = 16 p = 16 n = 20 p = 19 n = number of neutrons p = number of protons (a) What elements do these three atoms belong to respectively? (b) Write the atomic symbols (with atomic number and mass number) for these three atoms. Atom Atomic symbol (with atomic number and mass number) x y z 115 13 From Atoms to Materials Chapter Exercise © United Prime Educational Publishing (HK) Limited 2024 All rights reserved; no part of this publication may be reproduced, photocopied, recorded or otherwise, without the prior written permission of the Publisher. Sample