ionic bond

Question

Which of the following compounds has the highest lattice energy?

RankGuru · Accepted Answer

**Lattice Energy ($U$)** is the energy released when one mole of an ionic crystalline compound is formed from gaseous ions. According to **Coulomb's Law**:
$U \propto \frac{q_1 q_2}{r^0}$
Where $q_1, q_2$ are the charges and $r_0$ is the distance between ions.
- In **MgO**, ions are $Mg^{2+}$ and $O^{2-}$. The product of charges is $4$.
- In **NaCl**, ions are $Na^+$ and $Cl^-$. The product of charges is $1$.
- In **KBr**, ions are $K^+$ and $Br^-$. The product of charges is $1$.
- In **CaCl₂**, ions are $Ca^{2+}$ and $Cl^-$. Higher charge on $Ca$, but distance is larger.
Since $MgO$ has high charges and small ionic radii, it has the highest lattice energy.

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ionic bond

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