Aqa A-Level Chemistry 7405/1 Paper 1 Inorganic And Physical Chemistry Mark Scheme June 2023 Version: 1.0 Final

define first electron affinity {Ans: the enthalpy change when 1 mole of gaseous atoms gain 1 mole of electrons to form 1 mole of 1- ions.}what does the perfect ionic model assume? {Ans: The bonding in the compound is not 100% ionic. In the model the ions are perfect spheres/point charges are not distorted}Define enthalpy of lattice formation {Ans: The enthalpy change when 1 mole of an ionic compound is formed from its component gaseous ions}Define the term Ligand {Ans: Atom, ion or molecule which can donate a pair of electrons to a metal ion}Why is the experimental value for lattice dissociation of some compounds greater than the theoretical value? {Ans: the bonding is not 100% ionic/ there is some covalent character/ there is additional covalent bonding}Why is the enthalpy of hydration more exothermic for magnesium ions than calcium ions? {Ans: Mg ions are smaller They have a greater charge density The positive ion attracts the delta negative O more strongly}Define standard enthalpy of combustion {Ans: the enthalpy change when one mole of a substance is burned completely in excess oxygen with all products and reactants in their standard states under standard conditions}what