13.1.1 IONIC BONDING & STRUCTURES
29 September 2021
19:57
Lattice - Regular 3D arrangement of atoms or ions in a crystal.
Ionic bonding - Electrostatic force of attraction between oppositely charged ions in a
lattice.
13.1.2 ENERGY CHANGES & IONIC BONDING
29 September 2021
20:07
Standard enthalpy change of formation, ΔfH* - Enthalpy change when 1 mole of a
substance is formed from its constituent elements in standard states under standard
conditions.
, 13.1.3 ENTHALPY CHANGES WHEN IONS
FORM
29 September 2021
20:12
Standard enthalpy change of atomisation, ΔatH
Enthalpy change when 1 mole of gaseous atoms are formed from the element
in its standard state, under standard conditions.
1st electron affinity, Δe1H
Enthalpy change when 1 mole of gaseous atoms gain 1 mole of electrons to
form 1 mole of 1- gaseous ions, under standard conditions.
Adding first electron is exothermic for non-metals, but others are endothermic.
Electrostatic force of attraction to gain electron.
After first electron, becomes negatively charged, and so repels 2nd electron.
Ionic lattices are held together by a net force of oppositely charged ions.
When gaseous ions combine to form a lattice, energy is released.
Standard lattice energy, ΔleH*
Enthalpy change when 1 mole of an ionic substance is formed from its
constituent gaseous ions, under standard conditions.
Lattice energy is negative as forming lattice is exothermic.
The more negative, the stronger the ionic lattice.
If ions have smaller radii and have larger charges, higher charge density and can also
pack closer together if smaller.
Stronger electrostatic forces between ions, resulting in a more exothermic
lattice enthalpy.
29 September 2021
19:57
Lattice - Regular 3D arrangement of atoms or ions in a crystal.
Ionic bonding - Electrostatic force of attraction between oppositely charged ions in a
lattice.
13.1.2 ENERGY CHANGES & IONIC BONDING
29 September 2021
20:07
Standard enthalpy change of formation, ΔfH* - Enthalpy change when 1 mole of a
substance is formed from its constituent elements in standard states under standard
conditions.
, 13.1.3 ENTHALPY CHANGES WHEN IONS
FORM
29 September 2021
20:12
Standard enthalpy change of atomisation, ΔatH
Enthalpy change when 1 mole of gaseous atoms are formed from the element
in its standard state, under standard conditions.
1st electron affinity, Δe1H
Enthalpy change when 1 mole of gaseous atoms gain 1 mole of electrons to
form 1 mole of 1- gaseous ions, under standard conditions.
Adding first electron is exothermic for non-metals, but others are endothermic.
Electrostatic force of attraction to gain electron.
After first electron, becomes negatively charged, and so repels 2nd electron.
Ionic lattices are held together by a net force of oppositely charged ions.
When gaseous ions combine to form a lattice, energy is released.
Standard lattice energy, ΔleH*
Enthalpy change when 1 mole of an ionic substance is formed from its
constituent gaseous ions, under standard conditions.
Lattice energy is negative as forming lattice is exothermic.
The more negative, the stronger the ionic lattice.
If ions have smaller radii and have larger charges, higher charge density and can also
pack closer together if smaller.
Stronger electrostatic forces between ions, resulting in a more exothermic
lattice enthalpy.
