Among the following oxides, which has the maximum lattice energy?

Options

A. MgO
B. CaO
C. SrO
D. BaO

Answer

To determine which oxide has the maximum lattice energy among the given options (MgO, CaO, SrO, BaO), we can follow these steps:

### Step 1: Understand Lattice Energy
Lattice energy is the amount of energy released when one mole of an ionic compound is formed from its gaseous ions. It is influenced by two main factors:
- The charge of the ions: Higher charges lead to greater lattice energy.
- The size of the ions: Smaller ions lead to greater lattice energy due to closer proximity.

### Step 2: Identify the Oxides
The oxides given are:
- MgO (Magnesium oxide)
- CaO (Calcium oxide)
- SrO (Strontium oxide)
- BaO (Barium oxide)

### Step 3: Analyze the Charges
All the oxides listed are formed from Group 2 elements (alkaline earth metals), which have a +2 charge. Therefore, the charge factor is the same for all the oxides.

### Step 4: Analyze the Sizes
As we move down Group 2 from magnesium to barium, the size of the metal ions increases:
- Mg²⁺ < Ca²⁺ < Sr²⁺ < Ba²⁺

This means that magnesium is the smallest ion, while barium is the largest.

### Step 5: Apply the Lattice Energy Formula
Since lattice energy is directly proportional to the charge of the ions and inversely proportional to the size of the ions, we can conclude:
- All oxides have the same charge (+2).
- The smaller the ion, the greater the lattice energy.

### Step 6: Conclusion
Since Mg²⁺ is the smallest ion among the given options, MgO will have the highest lattice energy. Therefore, the oxide with the maximum lattice energy is:
**MgO**