ASRJC 2025 H2 Chem Periodic Table Notes

2025 ASRJC The Periodic Table (9729) 1 Illustration extracted from Concept of Chemical Periodicity: from Mendeleev Table to Molecular Hyper–Periodicity Patterns E. V. Babaev* and Ray Hefferlin+*Chemistry Department, Moscow State University, Moscow, 119899, Russia +Physics Department, Southern College, P.O. Box 370, Collegedale, TN 37315, USA ANDERSON SERANGOON JUNIOR COLLEGE 2025 JC2 H2 CHEMISTRY THE PERIODIC TABLE

2025 ASRJC The Periodic Table (9729) 2 LEARNING OBJECTIVES Trends and variations in atomic and physical properties For elements in the third period (sodium to chlorine), and in Group 2 (magnesium to barium) and Group 17 (chlorine to iodine): (a) Recognize variation in the electronic configurations across a Period and down a Group (b) Describe and explain qualitatively the trends and variations in atomic radius, ionic radius, first ionization energy and electronegativity: (i) Across a Period in terms of shielding and nuclear charge (ii) Down a Group in terms of increasing number of electronic shells and nuclear charge (c) Interpret the variation in melting point and in electrical conductivity across a Period in terms of structure and bonding in the elements (metallic, giant molecular, or simple molecular) (d) Describe and explain the trend in volatility of the Group 17 elements in terms of instantaneous dipole–induced dipole attraction Trends and variations in chemical properties For elements in the third period (sodium to chlorine): (e) (i) State and explain the variation in the highest oxidation number of the elements in oxides (for Na2O; MgO; Al2O3; SiO2; P4O10; SO3) and chlorides (for NaCl; MgCl2; AlCl3; SiCl4; PCl5) (ii) State and explain the variation in bonding in oxides and chlorides in terms of electronegativity (with the exception of AlCl3) (iii) Describe the reactions of the oxides with water (for Na 2O; MgO; A l2O3; SiO2; P 4O10; SO3) (iv) Describe and explain the acid/base behaviour of oxides (for Na 2O; MgO; Al2O3; SiO2; P4O10; SO3) and hydroxides (for NaOH; Mg(OH)2; Al(OH)3), including, where relevant, amphoteric behaviour in reaction with sodium hydroxide (only) and acids (v) Describe and explain the reactions of the chlorides with water (for NaCl; MgCl2; AlCl3; SiCl4; PCl5) (vi) Suggest the types of structure and bonding present in the oxides and chlorides from observations of their chemical and physical properties (f) Describe and deduce from E⦵ values the relative reactivity of elements of: (i) Group 2 as reducing reagents (ii) Group 17 as oxidising reagents (g) Describe and explain the trend in thermal stability of: (i) Group 2 carbonates in terms of the charge density of the cation and the polarisability of the large anion (ii) Group 17 hydrides in terms of bond energies In addition, students should be able to: (h) Predict the characteristic properties of an element i