S.6 Chemistry Of Group Vii (1) Caltec S.6

DEMYSTIFYING INORGANIC CHEMISTRY BY Joseph Jobs Kayiira , BScED(Hons.CHEM/MTC) Email;josephkayiirab@gmail.com call/Whats App 0753247098 pg. 1 THE CHEMISTRY OF GROUP VII ELEMENTS Electronic structures/ configurations Element Atomic number Configuration F 9 Cl 17 Br 35 I 53 From the above electronic configurations, it can be concluded that the outermost electronic configuration of group VII elements is Bonding and structure Element Bonding Structure Physical state and colour at room temperature Fluorine All covalent All simple molecular Pale yellow g as Chlorine Greenish yellow g as Bromine Red l iquid Iodine Grey/ black s olid Qn. Explain why fluorine and chlorine exist as gases whereas bromine and iodine exist as liquid and solid r espectively at room temperature From fluorine to iodine, atomic radius increases, molecular size and molecular mass increases, hence magnitude of Van der Waals’ forces of attraction holding the molecules increases in the order ; . The Van der Waals’ forces in bromine and iodine are strong enough to hold the molecules closer to each other existing as liquid and solid respectively. Fluorine and chlorine have weaker Van der Waals’ forces due to their small size and low molecular masses. Their molecules are therefore far apart. DEMYSTIFYING INORGANIC CHEMISTRY BY Joseph Jobs Kayiira , BScED(Hons.CHEM/MTC) Email;josephkayiirab@gmail.com call/Whats App 0753247098 pg. 2 VARIATION IN ATOMIC AND PHYSICAL PROPERTIES OF THE ELEMENTS 1. Melting poin ts/ boiling points The table below shows the boilin g points /melting points of halogens Explain the trend in boiling points / melting points of the halogens Boiling point/ melting point increases from fluorine to iodine because atomic radius increases, molecular size and molecular mass increases, hence magnitude of Van der Waals’ forces of attraction holding the molecules increases in the ord er . The energy required to break the forces therefore increase from fluorine to iodine …