Ionic Bonds : Coulomb's law, Lattice Energy

Rucete ✏ Chemistry In a Nutshell

Ionic Bonds

Coulomb's law

1 Metals or Groups 1A and 2A 

 1. Atoms of elements with low ionization energies

 2. Atoms tend to form cation (Li --> Li(+) + e(-) )

2 Nonmetals or Groups 6A and 7A 

 1. Atoms fo elements with high negative electron affinities

 2. Atoms tend to form anions (Cl + e(-) --> Cl(-) )

3 Coulomb's law

 1. Ions with opposite charges have the attraction between them.

 2.  The strength of the attraction can be calculate as Coulomb's law.

 3. Electrostatic attractive energy (E) is

 Where, K : a proportionality constant
      +q(q1) : charge on the cation
       -q(q2) : charge on the anion
        r : the distance between the nuclei of two ions

4 . Bigger charges mean stronger bonds
     smaller charges mean weaker bonds

5. Changes close together mean stronger bonds
    charges far apart mean weaker bonds

6 Most Ionic bonds can be distinguished by the difference in electronegativity.
--> If the difference in electronegativity is 1.7 or greater, it is classified as an ionic bond.
--> if the difference in electronegativity is less than 1.7, it is classified as covalent bond.

Lattice Energy 

1 The energy required to completely separate one mole of a solid ionic compound into gaseous ions.

2 Relating to the stability of the solid ionic compound.

3 Compounds with large lattice energy are generally stable and have high boiling points.