Question

Question:The molecules of a certain compound contain one atom each of nitrogen, fluorine, and oxygen. Two possible structures are NOF ( Oas a central atom) O NF and (N as a central atom). Does the information that the molecule is bent limit the choice to one of these two possibilities? Explain.

Short answer

This is a structure with a permanent positive formal charge on the oxygen, or a structure without formal charges but with an incomplete octet on nitrogen. So, molecular geometry is the ONF structure and most feasible option.

Step-by-step solution

Potential structure

Nitrogen, oxygen, and fluorineare molecular substances containing one atom of each.

The VSEPR theory and potential structures are crucial to the exercise. NOF or ONF are the two alternatives available. The molecule's geometry is also known to be bent. Assigning Lewis structures to the possibilities and finding the steric number of the central atom in both situations could aid in deciding whether the available information limits the choice to one of the possible structures.

Molecular geometry

The steric number is $SN=3L$with a lone pair on the central atom in both situations. The shapes of those structures are depicted in the graphic below, along with other "preliminary" attempts at Lewis structures. Both bent structures are viable, according to the VSEPR hypothesis.

Note that the Lewis structure on the left is intentionally imperfect.

When it comes to a realistic Lewis structure, the NOF order of the atoms causes some issues.

Because it is O, a Period 2 element with a stringent octet rule, the one given in the preceding step would have a hypervalent oxygen atom, which is impossible.

The only possible solutions (see image) are a structure with a permanent positive formal charge on the oxygen W or a structure without formal charges, but with an incomplete octet on nitrogen ($SN=4$also on the center oxygen), neither of which is desirable. So, regardless of the molecular geometry, the ONF structure is the most feasible option.

So, regardless of the molecular geometry, the ONF structure is the most feasible option.