After drawing the Lewis structure of carbonyl sulfide (CSO), which of the following best describes the polarity of the molecule?

• A. CSO is a polar molecule because it has an asymmetric distribution of electron density.
• B. CSO is a nonpolar molecule because its molecular geometry is linear and the dipoles cancel.
• C. CSO is a nonpolar molecule because all the atoms have similar electronegativities.
• D. CSO is a polar molecule because it contains only nonmetals.

Answer: (A)

Verified step by step guidance

1. Step 1: Draw the Lewis structure of carbonyl sulfide (CSO) by first counting the total valence electrons. Carbon (C) has 4, sulfur (S) has 6, and oxygen (O) has 6, giving a total of 16 valence electrons.
2. Step 2: Arrange the atoms with carbon in the center, sulfur on one side, and oxygen on the other, then distribute the electrons to satisfy the octet rule for each atom, forming double bonds as needed (typically C=O and C=S).
3. Step 3: Determine the molecular geometry. Since CSO is a triatomic molecule with a central atom bonded to two other atoms, the geometry is linear.
4. Step 4: Analyze the electronegativities of the atoms: oxygen is more electronegative than carbon, which is more electronegative than sulfur. This difference creates bond dipoles that do not cancel out due to the asymmetric distribution of electron density.
5. Step 5: Conclude that because the bond dipoles are unequal and the molecule is linear but asymmetric in terms of electronegativity, CSO is a polar molecule with an asymmetric distribution of electron density.