Which answer best describes an O_3/ozone molecule:
1. Each atom in ozone is connected to another atom by 1.5 bonds.
2.The double bond in ozone switches back and forth between the two outer oxygen atoms.
3.An ozone molecule contains one single bond and one double bond.
I want to go with #2 but I am not 100% positive. I know that there can only be 2 different resonance structures for ozone...and what they are to look like...but is there a better answer than #2??
#2 can't be right. Just remember that resonance structures are NOT one thing part of the time and another thing at another time; i.e., they do NOT switch back and forth. They are a hybrid bond, not an alternating from one to another bond.
#3 can't be right. As you correctly point out, we know there are two resonance hybrids we can draw.
So that leaves #1 as the only plausible answer. The texts I read say O-O bond length is intermediate between a single bond and a double bond. And that would be about 1.5 bonds.
The correct answer is #3. An ozone molecule contains one single bond and one double bond. The double bond is formed between the central oxygen atom and one of the outer oxygen atoms. Ozone exhibits resonance, which means that the double bond is not fixed between the two outer oxygen atoms but rather delocalized throughout the molecule, resulting in two equivalent resonance structures.
To determine the correct answer, let's examine the structure of an O3/ozone molecule and its resonance structures.
An ozone molecule consists of three oxygen atoms, denoted as O-O-O. In its conventional Lewis structure, one oxygen atom forms a double bond with the central oxygen atom, while the other oxygen atom forms a single bond with the central atom. This arrangement is known as the Lewis structure of ozone.
Now, let's consider the concept of resonance structures. Resonance occurs when multiple Lewis structures can be drawn for a molecule, indicating that the actual structure of the molecule is a combination of these resonance forms.
In the case of ozone, it is indeed possible to draw two distinct resonance structures. One resonance structure involves the double bond formation between the central and one of the outer oxygen atoms (O=O-O), while the other resonance structure involves the double bond formation between the central oxygen atom and the other outer oxygen atom (-O=O-O).
Now, let's evaluate each answer choice in light of this information:
1. Each atom in ozone is connected to another atom by 1.5 bonds: This statement is incorrect. Each oxygen atom in ozone is connected to another oxygen atom either by a single bond or a double bond, but not by a 1.5 bond.
2. The double bond in ozone switches back and forth between the two outer oxygen atoms: This statement correctly describes the phenomenon of resonance in ozone. The double bond is delocalized or shared between the two outer oxygen atoms, meaning that it "switches" or alternates between them.
3. An ozone molecule contains one single bond and one double bond: This statement is partially correct. Ozone does contain a single and a double bond, but the double bond is not fixed between the central and one outer oxygen atom. It is shared or delocalized over both outer oxygen atoms due to resonance.
Therefore, the best answer to describe an ozone molecule is indeed option #2.