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Finding the oxidation number of N in KNO2
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Topic: Finding the oxidation number of N in KNO2 (Read 5616 times)
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kstervic
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Finding the oxidation number of N in KNO2
«
on:
September 06, 2014, 06:44:28 PM »
Hi I am having some trouble with one particular question.
The question is: What is the oxidation number for the atom N is KNO
2
?
This is the explanation I got.
It looks like we have 2 unknown oxidation numbers (K & N), but the truth is that there is only one unknown (N). This is because KNO2 is a polyatomic (because it is called potassium nitrite, & nitrite is a polyatomic ion). Since polyatomic molecules are ionic, this means we know that the oxidation number of K must be +1 by the uncriss-crossing rule. We then look at O & its oxidation number is -2. The molecule is neutral, so the algebraic expression equals 0. We then solve as usual.
I understand every line of that explanation except how we find the oxidation number of K.
How do we use the uncriss-crossing rule to find that K has a charge of +1?
Thank you in advance!
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Borek
Mr. pH
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I am known to be occasionally wrong.
Re: Finding the oxidation number of N in KNO2
«
Reply #1 on:
September 07, 2014, 03:37:12 AM »
One of the basic rules when assigning oxidation numbers is that alkali metals (Li, Na, K, Rb, Cs) are always +1.
What they probably mean is that NO
2
-
is known to be -1 as a group, so potassium must be K
+
(or +1).
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ChemBuddy
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Partha Sarker
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Re: Finding the oxidation number of N in KNO2
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Reply #2 on:
September 11, 2014, 02:53:19 AM »
It will be +3
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Finding the oxidation number of N in KNO2