za said:
when ozone reacts only one bond needs to be broken, releasing an O and leaving behind oxygen
The bond order of ozone is not 1 nor is it 2. When you draw the Lewis structure of ozone, you will find that the central Oxygen atom is double-bonded to one and single-bonded to the other. Thus, two Lewis structure for ozone can be drawn (when you consider each Oxygen atom to be unique) and in reality you can imagine that it shifts between the two structures - this is known as resonance hybrid.
As mystify has mentioned, this is a type of coordinate covalent bond - meaning one atom donates both electron when bonding. One way to think of the actual bonding in ozone is "one and a half bond" to each Oxygen. Technically we define this type of bonding as
delocolised where electron pair in the central Oxygen is shared by both of the other two Oxygen atoms. (Not required for the HSC)
Clearly the bonding in ozone is less stable than the bonding in O
2 and thus ozone is reactive and is easily decomposed into O
2 and an O. radical when sufficient energy is supplied (UV).
For the comparison between radical Oxygen atom and O
2 I think there is a table in Conquering Chemistry or the Excel HSC Chemistry if not CC. Good luck!