Reactivity of ozone (1 Viewer)

[mystify]

Im hoping someone might be able to help me....I was going through some syllabus points and came across one where you have to compare the properties of gaseous forms of oxygen and the oxygen free radical. Does the coordinate covalent bond in ozone account for its reactivity and if so how? Thanks for any help...

 

[Tommy_Lamp]

hmmzt im not to sure about this one
what i do know is that the free-radical is much more reactive then the diatomic oxygen because of its two unpaired electrons. not sure about 'other' properties.
for the ozone part, the two identical oxygen to oxygen bonds in ozone consist of a single bond and a partial bond. this results in lower stability of the ozone molecule, compared with the diatomic oxygen molecule. thus making it more reactive.

 

[za]

yeah thats true.
the splitting of the diatiomic oxygen double bond requires considerable amounts of energy, however when ozone reacts only one bond needs to be broken, releasing an O and leaving behind oxygen.

 

[xiao1985]

oxygen free radical is not ozone tho... which one are you referrin to???

 

[iambored]

yes mystify, you realise you are talking about 3 things:

O (+/- i can't remember, it's the free radical)
O2 oxygen
O3 ozone

 

[mervvyn]

O radical has no charge, it's just a single lonely O atom - that's why it's so reactive, because it can't stand being lonely like that.

I thought the syllabus only required us to look at O2 and O3 and compare, not O radicals as well...

 

[mitochondria]

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 O2 and thus ozone is reactive and is easily decomposed into O2 and an O. radical when sufficient energy is supplied (UV).

For the comparison between radical Oxygen atom and O2 I think there is a table in Conquering Chemistry or the Excel HSC Chemistry if not CC. Good luck!

 

[mr EaZy]

maybe its my eyes and this exceedingly bright monitor which i will now adjust, but my head hurts after reading that. let me break it down.

The bond order of ozone is not 1 nor is it 2.

What does this mean?

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.

0=0-0 where the final 0-0 bond is the coord cov bond correct??

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.

yeah ok.

Clearly the bonding in ozone is less stable than the bonding in O2 and thus ozone is reactive and is easily decomposed into O2 and an O. radical when sufficient energy is supplied (UV).

is the reactivity of ozone what is responsible for it being more soluble in water./???

also when drawing a lewis diagram u have to leave the Xs and the Os as they are right? for some reason i found myself drawing a loop around a pair of X and Os to show that the XO had formed a covalent bond. Is this wrong??????

thnx all!

 

[mitochondria]

Sorry

Bond order: how many pairs of electron are shared between two atoms, e.g. in O=C=O, the OC bond has a bond order of 2.

Lewis structure of ozone: exactly the one you have drawn

Coordinated covalent bond: yes, as in the O-O in O=O-O, however, remember that we technically think of it as one and a half bond - imagine a pair of electron contributed by the central Oxygen atom spends its time between all three atoms.

I don't think ozone being more soluble in water is because of its reactivity. Ozone has a higher molecular weight than O2, together with its delocalised electrons (lower electron density) the dispersion force between Ozone and water is greater than that of O2, thus more soluble.

------> what do you mean by the Xs and Os? *confused*

 

[mr EaZy]

i see, the fact that the central oxygen atom can share an electron with the first oxygen atom and at the same time provide 2 electrons to the third ( and therefore having these two electrons circulate between the 3 oxygen atoms ) ..... this would decrease electron density compared to a normal oxygen atom and hence increase solubility (along with the fact that is has more molecular weight than 02)

ok then, now the X0s???
some (i dunno which) would repesent the electron dot diagram as follows

.. ..
:0 : : 0 : 0 : but other texts will put X's to show that this electron came from ...
.. ..



another atom to not get us confused. but should we leave it like this or do we put a circle around the electron pairs?

 

[tennille]

put circles around the the electrons that are being shared. Leave the electrons as one shape- either dots or crosses.

 

[tennille]

that's pretty much what my chemistry teacher told me.

 

[xiao1985]

@mitocondria: agreed =) btw,the X's and O's i think is meant to be electrons from oxygen atom A or oxygen atom B...

@ mervvy: i think u will need to know the oxygen radical as well...

@mr easy: the solubility is i think largely due to the bent structure of ozone... (ie, i think awhile ago, we had a discussion on this, and ozone is polar!! despite being purely made up of oxgen )

 

[mervvyn]

yeah, you're right, i checked the syllabus, we have to compare O2 and O3 and then molecular oxygen and oxygen radicals...