Unit 7 – The p-Block Elements Class 12 Notes | Group 15, 16, 17, 18 Elements Explained | CBSE Chemistry 2025
Unit 7: The p-Block Elements 7.1 Group 15 Elements 7.2 Dinitrogen 7.3 Ammonia 7.4 Oxides of Nitrogen 7.5 Nitric Acid 7.6 Phosphorus – Allotropic Forms 7.7 Phosphine 7.8 Phosphorus Halides 7.9 Oxoacids of Phosphorus 7.10 Group 16 Elements 7.11 Dioxygen 7.12 Simple Oxides 7.13 Ozone 7.14 Sulphur – Allotropic Forms 7.15 Sulphur Dioxide 7.16 Oxoacids of Sulphur 7.17 Sulphuric Acid 7.18 Group 17 Elements 7.19 Chlorine 7.20 Hydrogen Chloride 7.21 Oxoacids of Halogens 7.22 Interhalogen Compounds 7.23 Group 18 Elements I. General Properties and Trends in p-Block Elements Affinity for Hydrogen and Bond Dissociation Enthalpy The affinity for hydrogen decreases as you go down the group from fluorine to iodine within the halogens ``. Consequently, the highest bond dissociation enthalpy among halogen acids (HF, HCl, HBr, HI) is found in HF ``. This implies a stronger bond that is harder to break. Reducing Behavior and Bond Dissociation Enthalpy The strength of a reducing ag...