Question

Which of the following molecules or ions will have a lewis structure most like that of phosphorous trichlorid, PCl3? a) ClO3- b) SO3 c) (CO3)2- d) BF3

Answer 1

While none of the options perfectly match PCl3 since it has a lone pair and a trigonal pyramidal shape, SO3 is the closest as it has a central atom with the same number of valence electrons as phosphorous in PCl3.

Step-by-step explanation:

The molecule or ion that will have a Lewis structure most like that of phosphorous trichloride, PCl3, from the given options is SO3. In PCl3, phosphorous has three bonding domains with chlorine and one lone pair, making its shape trigonal pyramidal. Looking at the options:

• ClO3- will have a trigonal pyramidal shape since the central atom, Cl, has three bonds with O atoms and one lone pair.
• SO3 will have a trigonal planar shape since the central S atom has three bonds with O atoms and no lone pairs.
• (CO3)2- will also have a trigonal planar shape similar to SO3 because the central C atom has three bonds with O atoms and no lone pairs.
• BF3 will have a trigonal planar shape since the central B atom has three bonds with F atoms and no lone pairs.

Although SO3 and (CO3)2- both have trigonal planar shapes and BF3 has a similar shape, SO3 is most like PCl3 because it has the same number of valence electrons in its central atom as phosphorous. However, none of the options provided are a perfect match since PCl3 has a lone pair and therefore has a different geometry.

Answer 2

Among the given molecules or ions, BF3 will have a Lewis structure most like that of phosphorus trichloride, PCl3.

Step-by-step explanation:

The Lewis structure of phosphorus trichloride, PCl3, consists of a central phosphorus atom bonded to three chlorine atoms.

To determine which of the given molecules or ions will have a Lewis structure most like that of PCl3, we need to look for similar central atoms bonded to the same number of surrounding atoms.

Among the options, the molecule that fits this description is d) BF3. It has a central boron atom bonded to three fluorine atoms, just like PCl3.