In: Chemistry
Ionic strength depends on attraction or repulsion that can be explained with Coulomb's law. Energy of attraction or repulsion between two particles is comparable to the multiplication of two charges and inversely comparable to the distance between two particles.
Ions in LiF and MgO have same size, this indicates the distance between 2 particles in compound is same. So, the thing that affect the ionic strength is the charge of each compound. Ions in LiF has smaller energy than MgO because MgO ions (Mg 2+ charge and O 2- charge) have bigger charge than the LiF (Li +1 and F -1 charge). Hence MgO has strong ionic bonding when compared to LiF.