Which of the following statements correctly describes the Lewis dot structure of the KrF_2 molecule?

• A. Krypton has no lone pairs, and each fluorine atom has three lone pairs; the Kr–F bonds are single bonds.
• B. Krypton has two lone pairs, and each fluorine atom has two lone pairs; the Kr–F bonds are double bonds.
• C. Krypton has three lone pairs, and each fluorine atom has three lone pairs; the Kr–F bonds are single bonds.
• D. Krypton has four lone pairs, and each fluorine atom has two lone pairs; the Kr–F bonds are single bonds.

Answer: (C)

Verified step by step guidance

1. Step 1: Determine the total number of valence electrons available for bonding in KrF_2. Krypton (Kr) is a noble gas in group 18 with 8 valence electrons, and each fluorine (F) atom has 7 valence electrons. Since there are two fluorine atoms, total valence electrons = 8 (Kr) + 2 × 7 (F) = 22 electrons.
2. Step 2: Draw the skeletal structure with krypton as the central atom bonded to two fluorine atoms. Connect each fluorine to krypton with a single bond initially, which uses 2 electrons per bond, totaling 4 electrons used.
3. Step 3: Distribute the remaining electrons to satisfy the octet rule for the fluorine atoms first. Each fluorine needs 6 more electrons (3 lone pairs) to complete its octet after the single bond.
4. Step 4: Assign the leftover electrons to the central krypton atom. After placing lone pairs on fluorines, count how many electrons remain and place them as lone pairs on krypton. Remember that krypton can have an expanded octet because it is in period 4.
5. Step 5: Confirm the number of lone pairs on krypton and fluorine atoms and the bond types. Verify that each fluorine has three lone pairs, the Kr–F bonds are single bonds, and count the lone pairs on krypton to match the correct Lewis structure.