Calculate the force of attraction between a ca^2+ and an 0^2- irons whose centers are sep by a distance of 1.25 nm.

Solution:

Given:

Calcium and Oxygen ions each having valence = 2 or 2 valence electrons

seperation distance, r = 1.25nm = m

Coulombian force for two point charges seperated by a distance 'r' is given by:

F =      (1)

Now, we know that

q = ne

where, n = no. of electrons

e = charge of an electron = C

= e = 2e

= e = 2e

Using Eqn (1)

F =

F = N

Since, the force is between two opposite charged ions, it is attractive in nature.

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