From Atoms to Materials

Checkpoint 13.2B (a) (d) (b) (e) (c) 1. (a) A proton has a (i) (positive / negative / neutral) electric charge. An electron has a (ii) (positive / negative / neutral) electric charge. (b) T he (i) number of an atom is the number of protons in it. The (ii) number of an atom is the sum of the numbers of protons and neutrons in it. 2. Complete the following table, without referring to Table 13.2. Atom Number of Atomic number Mass number protons electrons neutrons (a) Boron 5 6 (b) Phosphorus 15 16 (c) Aluminium 13 27 (d) Silver 60 47 (e) Iron 26 56 3. Write the atomic symbol (with atomic number and mass number) for each atom in Q2. 20 © 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