Aqa A-Level Chemistry: The Ultimate Complete Revision & Exam S

AQA A-Level Chemistry: The Ultimate Complete Revision & Exam Success Masterclass AQA Chemistry A level What makes transition metal characteristics incomplete d sub-level in atoms or ions 4 main characteristics of Transition metals complex formation, formation of coloured ions, variable oxidation state, catalytic activity what is a complex a central metal ion surrounded by ligands what is a ligand An atom, ion or molecule which can donate a lone electron pair what is a coordinate bond Co-ordinate bonding is when the shared pair of electrons in the covalent bond come from only one of the bonding atoms what is coordination numberThe number of co-ordinate bonds formed to a central metal ion why is carbon monoxide toxic CO is toxic to humans as CO can from a strong coordinate bond with haemoglobin. This is a stronger bond than that made with oxygen and so it replaces the oxygen attaching to the haemoglobin what is the chelate effect The substitution of monodentate ligand with a bidentate or a multidentate ligand leads to a more stable complex. This chelate effect can be explained in terms of a positive entropy change in these reactions as more molecules of products than reactants type of isomerism