F = k * (q1 * q2) / r²
where:
* F is the force
* k is Coulomb's constant
* q1 and q2 are the charges of the particles
* r is the distance between the particles
From this formula, we can see that the force is inversely proportional to the square of the distance. This means that if you double the distance (r), the force will be reduced by a factor of 2² = 4.
Therefore, the electrical force between a pair of ions is reduced by a factor of 4 when their separation distance is doubled.
