Lattice Enthalpy 7 Flashcards
Define ionic bonding
Strong electrostatic force of attraction between oppositely charged ions
Define lattice enthalpy
The enthalpy change when 1 mole of a solid ionic lattice is formed from its gaseous ions
What type of enthalpy change is bond making
Bond making is exothermic. As the ions are forming attractions with each other they are making bonds so lattice enthalpy values are always negative
Describe the strength of the ionic bonds as the lattice enthalpy becomes more negative
The stronger the ionic bonds
What factors affect the value of lattice enthalpy
. Ionic charge- the greater the charge the stronger the attraction for ions of opposite charge
. Ionic radius- the smaller the radius the better
Define standard enthalpy change of formation
The enthalpy change when 1 mole of a compound is formed from its elements
In their standard states under standard conditions
Define standard enthalpy change of atomisation
The enthalpy change when 1 mole of gaseous atoms are formed from an element
In its standard state
Define standard first ionisation energy
The enthalpy change when 1 mole of electrons is removed from 1 mole of gaseous atom
Define standard second ionisation energy
The enthalpy change when 1 mole of electrons is removed from 1 mole of a singly positive gaseous ion
Define standard first electron affinity
The enthalpy change when 1mole of gaseous 1- ion are made from 1 mole of gaseous atom
Define standard second electron affinity
The enthalpy change when 1 mole of gaseous 2- ions are made from 1 mole of gaseous 1- ion
Why are second electron affinities endothermic
Energy is needed to overcome the repulsion between negatively charged ion and an electron
Define Hess’s Law
The enthalpy change of a reaction is independent of the route taken providing the initial and finale conditions remain the same
