Question

Which of the following has higher lattice energy -$A{l}_2{O}_3$ or $A{l}_{2}S{e}_3$?

• A. $A{l}_2{O}_3$ > $A{l}_{2}S{e}_3$
• B. $A{l}_2{O}_3$ < $A{l}_{2}S{e}_3$
• C. $A{l}_2{O}_3$ = $A{l}_{2}S{e}_3$
• D. None of these

Answer 1

The correct option is A $A{l}_2{O}_3$ > $A{l}_{2}S{e}_3$

Lattice Energy is directly proportional to the charge on the ions and inversely proportional to the size of the ions. The two species have the same charge but the size of $Se$ is greater than $O$. Hence lattoce energy of $A{l}_2{O}_3$ is greater than $A{l}_{3}S{e}_3$.