OXIDATION NUMBERS urgent

Hey guys,

I'm currently doing oxidation numbers, and I find it difficult finding the oxidation number of a less familiar element (Basically an element tha's not oxygen or hydrogen or fluorine as I know they're oxidation numbers).

For example:

Deduce the oxidation state of each bold element:

NaClO₃ - Each of oxygen is -2, so in total oxygen is -6. But how am I am able to work out Na and Cl???

KMnO₄ - Likewise with this question also.

Thank you!

Reply 1

langlitz

17

Original post by rm_27

Hey guys,

I'm currently doing oxidation numbers, and I find it difficult finding the oxidation number of a less familiar element (Basically an element tha's not oxygen or hydrogen or fluorine as I know they're oxidation numbers).

For example:

Deduce the oxidation state of each bold element:

NaClO₃ - Each of oxygen is -2, so in total oxygen is -6. But how am I am able to work out Na and Cl???

KMnO₄ - Likewise with this question also.

Thank you!

Have you ever seen a group one metal in a state other than +1? If so, I take my hat off to you. But I haven't...

So 1+Cl+(-6)=0
Cl=+5
and
1+Mn+(-8)=0
Mn=+7

Reply 2

Borek

4

Just follow the rules, as explained here:

http://www.chembuddy.com/?left=balancing-stoichiometry&right=oxidation-numbers-method

One of the rules is "alkali metals are always +1". After that both your examples become trivial, as shown by langlitz.

Original post by rm_27

Hey guys,

I'm currently doing oxidation numbers, and I find it difficult finding the oxidation number of a less familiar element (Basically an element tha's not oxygen or hydrogen or fluorine as I know they're oxidation numbers).

For example:

Deduce the oxidation state of each bold element:

NaClO₃ - Each of oxygen is -2, so in total oxygen is -6. But how am I am able to work out Na and Cl???

KMnO₄ - Likewise with this question also.

Thank you!

Here's an interactive self test on oxidation numbers ... enjoy