Question

Arrange the following in the increasing order of the strength of ionic bond-

a K₂O
b CaO
c MgO
d KCl

A cdba
B bcda
C dabc
D acdb

Answer 1

Ionic bond strength increases with higher charges and smaller ionic sizes. KCl has the weakest bond, followed by K2O, then CaO, with MgO having the strongest bond due to its smallest cation and both ions having a ±2 charge.

Step-by-step explanation:

The strength of an ionic bond is influenced by the charge on the ions and the size of the ions. Higher charges and smaller sizes generally result in stronger ionic bonds. To arrange K2O, CaO, MgO, and KCl in order of increasing ionic bond strength, we consider both the charge and relative size of the ions in each compound.

1. KCl has ions with a +1 and -1 charge and larger radii, so it has the weakest ionic bond.
2. K2O has a metal with a +1 charge but the oxide anion has a -2 charge, making the bond stronger than in KCl due to the increased charge of the oxide anion.
3. CaO has ions both with a +2 charge (smaller Ca2+ compared to K+) and a -2 charge (O2-), resulting in a stronger bond than K2O.
4. MgO has the smallest cation (Mg2+) with a +2 charge and an oxide anion with a -2 charge, resulting in the strongest ionic bond among the given compounds.

Hence, the correct order from weakest to strongest ionic bond is KCl < K2O < CaO < MgO.