Given the molecule HArF, what is the average bond order of the H–Ar and Ar–F bonds?

• A. 1
• B. 3
• C. 2
• D. 0.5

Answer: (A)

Verified step by step guidance

1. Step 1: Understand the concept of bond order. Bond order is defined as the number of chemical bonds between a pair of atoms. It can be calculated as the difference between the number of bonding electrons and antibonding electrons divided by two, or simply by counting the bonds in the Lewis structure if available.
2. Step 2: Analyze the molecule HArF. This is a rare and unusual molecule where argon (Ar), a noble gas, forms bonds with hydrogen (H) and fluorine (F). The bonding is typically considered to involve one bond between H and Ar, and one bond between Ar and F.
3. Step 3: Determine the bond order for each bond. Since HArF is known to have a single bond between H and Ar, and a single bond between Ar and F, each bond has a bond order of 1.
4. Step 4: Calculate the average bond order by adding the bond orders of H–Ar and Ar–F bonds and dividing by 2: \(\text{Average bond order} = \frac{\text{Bond order}_{H-Ar} + \text{Bond order}_{Ar-F}}{2}\).
5. Step 5: Substitute the bond orders (both 1) into the formula to find the average bond order without calculating the final numeric value explicitly.