Question

Select a molecule and/or polyatomic ion in which the molecular shape is different than the electron arrangement. specify the molecular formula or letter that corresponds to the correct molecule and explain your reasoning in 1-2 sentences. include a picture of their lewis structures (that you must draw by hand), if needed, as part of your explanation.

(a) CO₂
(b) H₂O
(c) NO₃⁻
(d) CCl₄

Answer 1

(b) H₂O. (water) is an example of a covalent molecule where the molecular shape (bent) differs from the electron pair arrangement (tetrahedral) around the oxygen atom due to lone pair repulsion.

Step-by-step explanation:

To find a molecule or polyatomic ion where the molecular shape is different from the electron arrangement, we consider option (b) H₂O. The molecular formula for water is H₂O, which is a covalent substance.

Water's Lewis structure shows two lone pairs of electrons on the oxygen atom and two bonding pairs, which result in a bent molecular shape due to the electron pair repulsion.

However, if we only consider the electron pair arrangement around the oxygen, we get a tetrahedral arrangement. The molecular geometry of water is different from the electron arrangement primarily because of the repulsions between the two lone pairs and the bonding pairs.