Oxidation States (1 Viewer)

[Viper]

Hey all,

I just realised that i have forgotten everything about Oxidation States and Numbers. I have had a quick read of the text book, and it doesn't seem to make sense.

Could someone please give a brief description of the basic rules of oxidation number for each element and their application?

Cheers

 

[BlackJack]

Oxidation states of elements in a molecule describe the charge atoms would have if ALL bonding electrons went to the more electronegative element of the pair.
i.e. For CO2, C becomes +4.

Home-made rules:

Hydrogen = +1
Oxygen = - 2
(a few exceptions like LiH)
Group 1 should all have +1, group 2s +2.

All numbers must add up to the charge on the molecule:

eg.
Cr2O7(2-)
7 Oxygens, subtotal -14 charge.
2(Cr) -14 = -2
Cr = +6

Makes it convenient, as different ox. states have different properties, compare iron (III) and iron (II).

Read your textbook again. It's probably easier than you think.

 

[Ragerunner]

all i remember is making the oxidation state equal to zero and then work out the other species state by making them add to zero

 

[Viper]

Yeah, thanks *BlackJack*,

I remember now... It was the rules that i couldn't remember... but i was thinking... Are Oxidation States in the HSC course? Or the preliminary course? Anyone?


Cheers

 

[abdooooo!!!]

its in hsc: 1st module 4th section or in shipwrecks

not sure if its in prelim...