In the Lewis dot structure of ClF_3, how many lone pairs are present on the central chlorine atom?

• A. 3
• B. 1
• C. 0
• D. 2

Answer: (D)

Verified step by step guidance

1. Step 1: Determine the total number of valence electrons for the molecule ClF_3. Chlorine (Cl) has 7 valence electrons, and each fluorine (F) atom has 7 valence electrons. Since there are 3 fluorine atoms, total valence electrons = 7 (Cl) + 3 × 7 (F) = 28 electrons.
2. Step 2: Draw the skeletal structure with chlorine as the central atom bonded to three fluorine atoms. Each Cl–F bond represents 2 electrons, so 3 bonds use 6 electrons.
3. Step 3: Subtract the bonding electrons from the total valence electrons to find the remaining electrons: 28 - 6 = 22 electrons left to be placed as lone pairs.
4. Step 4: Assign lone pairs to the fluorine atoms first to complete their octets. Each fluorine needs 3 lone pairs (6 electrons), so 3 fluorines × 6 electrons = 18 electrons assigned to fluorine lone pairs.
5. Step 5: The remaining electrons (22 - 18 = 4 electrons) are placed as lone pairs on the central chlorine atom. Since each lone pair consists of 2 electrons, chlorine has 2 lone pairs.