Question

Elements $Se$, $Cl$ and $S$ have been arranged in the order of increasing ionisation energies. Identify the correct order.

• A. $S<Se<Cl$
• B. $Se<S<Cl$
• C. $Cl<S<Se$
• D. $Se=S<Cl$

Answer 1

The correct option is B $Se<S<Cl$

Ionisation energy generally increase from left to right across a row of the Periodic Table and decreases from top to bottom down a group. Hence, IE of $Cl>S$ and IE of $Se<S$. Thus, the order is $Se<S<Cl$.