From Atoms to Materials

The growing Periodic Table When Mendeleev organized his Periodic Table of elements, only about 65 elements had been discovered. Now the Periodic Table has a total of 118 elements. As new elements are discovered or synthesized, the Periodic Table keeps on expanding. Nature of Science Nh 113 Mc 115 Ts 117 Og 118 In June 2016, four new elements (atomic numbers 113, 115, 117 and 118) were added to the Periodic Table. This shows that scientific knowledge continues to develop. Checkpoint 13.3A 1. In the Periodic Table, the vertical columns are called (a) , and the horizontal rows are called (b) . 2. By referring to the Periodic Table in the Appendix, complete the following Table. Period Group Atomic number Name of element Chemical symbol 2 II (a) (b) (c) 4 I (d) (e) (f) (g) (h) 18 (i) (j) (k) (l) (m) silicon (n) (o) (p) (q) (r) F 3. B y referring to the Periodic Table in the Appendix, state what period and what group the following elements belong to. Period Group (a) lithium (b) carbon (c) sulphur (d) calcium 33 13 From Atoms to Materials © 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