NJC 3 Atomic Structure

National Junior College SH1 H2 Chemistry 1 ATOMIC STRUCTURE Content: • The nucleus of the atom: neutrons and protons, isotopes, proton and nucleon numbers • Electrons: electronic energy levels, ionisation energies, atomic orbitals, extranuclear structure (empty space around the nucleus where electrons can be found) Learning Outcomes required for H1 (8873) & H2 (9729) Chemistry: Students should be able to: (a) identify and describe protons, neutrons and electrons in terms of their relative charges and relative masses (b) deduce the behaviour of beams of protons, neutrons and electrons in an electric field (c) describe the distribution of mass and charges within an atom (d) deduce the numbers of protons, neutrons and electrons present in both atoms and ions given proton and nucleon numbers (and charge) (e) describe the contribution of protons and neutrons to atomic nuclei in terms of proton number and nucleon number (f) describe the number and relative energies of the s, p and d orbitals for the principal quantum numbers 1, 2 and 3 and also the 4s and 4p orbitals (g) describe the shapes of s, p and d orbitals [knowledge of wave functions is not required] (h) state the electronic configuration of atoms and ions given the proton number (and charge) (i) explain the factors influencing the ionisation energies of elements (j) deduce the electronic configurations of elements from successive ionisation energy data (k) interpret successive ionisation energy data of an element in terms of the position of that element within the Periodic Table All Rights Reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopy, recording or any other information storage and retrieval system, without prior permission in writing from the copyright owner. Copyright © 2023 National Junior College

National Junior College SH1 H2 Chemistry 2 1. INTRODUCTION The interactions between the valence electrons of 2 or more atoms lead to chemical combinations between them. Hence the chemical properties of an element are largely determined by the number of valence electrons each of its atoms possesses. The study of the electronic structure of atoms, i.e. the detaile d arrangement of electrons of an atom, is therefore of fundamental importance in the understanding of chemical behaviors of elements. Success criteria: • Identify and describe protons, neutrons and electrons in terms of their relative charges and relative masses. • Define nucleon number (mass number) and proton number (atomic number). • Deduce the numbers of protons, neutrons and electrons present in both atoms and ions given proton and nucleon numbers (and charge). Note: As the mass of electron is insignificant compared to mass of p