Oxidation state
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104922499 1F
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Re: Oxidation state
There are a couple standard rules that will help determine the oxidation states of certain atoms in molecules.
Hydrogen always has a +1 oxidation state.
Oxygen almost always has a -2 oxidation state (unless its with H2O2).
Let's find out the oxidation state of oxygen in H2O2 as an example.
We know that hydrogen has a +1 oxidation state, and the overall charge on the molecule is 0. If we were to assign "x" to the oxidation state of oxygen, we would get +1(2) because we have 2 hydrogen atoms and 2x because we have 2 oxygen atoms.
+1(2) + 2x = 0
When we solve it out, we get that x = -1, and so the oxidation state of oxygen in this molecule is -1.
Here's another example:
MnO4-
We can assume that the oxidation number of oxygen is -2. The overall charge of the molecule is -1. Thus, the math we have to solve for is x + 4(-2) = -1.
When solving for x, we get x = +7, and so the oxidation state of manganese in this example is +7.
Hope this helps!
Hydrogen always has a +1 oxidation state.
Oxygen almost always has a -2 oxidation state (unless its with H2O2).
Let's find out the oxidation state of oxygen in H2O2 as an example.
We know that hydrogen has a +1 oxidation state, and the overall charge on the molecule is 0. If we were to assign "x" to the oxidation state of oxygen, we would get +1(2) because we have 2 hydrogen atoms and 2x because we have 2 oxygen atoms.
+1(2) + 2x = 0
When we solve it out, we get that x = -1, and so the oxidation state of oxygen in this molecule is -1.
Here's another example:
MnO4-
We can assume that the oxidation number of oxygen is -2. The overall charge of the molecule is -1. Thus, the math we have to solve for is x + 4(-2) = -1.
When solving for x, we get x = +7, and so the oxidation state of manganese in this example is +7.
Hope this helps!
Re: Oxidation state
Assuming your asking about assigning oxidation numbers, there are a few rules to follow.
1) atoms in their natural state are assigned 0 (e.g., Al, H2)
2) monatomic ions are assigned their charge (e.g., Na+ = +1)
3) neutral compounds are assigned 0 (e.g., CO2)
4) polyatomic ions are assigned their overall charge (e.g., NH4+ = +1)
5) Group 1 atoms in a compound are assigned +1 (e.g., Li = +1)
6) Group 2 atoms in a compound are assigned +2 (e.g., Mg = +2)
7) oxygens in a compound are usually assigned -2 (e.g., H2O)
8) oxygens in any peroxide are assigned -1 (e.g., H2O2)
9) oxygens paired to fluorine are assigned +2 (e.g., OF2)
10) hydrogens in a compound are usually assigned +1 (e.g., H2O)
11) hydrogens in binary metal hydride are assigned -1 (e.g., LiH)
12) fluorines are always assigned -1
13) chlorine, bromine, and iodine are assigned -1 unless paired with fluorine or oxygen
I think that's all of them. A lot of the rules are usually grouped together. I was just trying to be as clear as possible.
1) atoms in their natural state are assigned 0 (e.g., Al, H2)
2) monatomic ions are assigned their charge (e.g., Na+ = +1)
3) neutral compounds are assigned 0 (e.g., CO2)
4) polyatomic ions are assigned their overall charge (e.g., NH4+ = +1)
5) Group 1 atoms in a compound are assigned +1 (e.g., Li = +1)
6) Group 2 atoms in a compound are assigned +2 (e.g., Mg = +2)
7) oxygens in a compound are usually assigned -2 (e.g., H2O)
8) oxygens in any peroxide are assigned -1 (e.g., H2O2)
9) oxygens paired to fluorine are assigned +2 (e.g., OF2)
10) hydrogens in a compound are usually assigned +1 (e.g., H2O)
11) hydrogens in binary metal hydride are assigned -1 (e.g., LiH)
12) fluorines are always assigned -1
13) chlorine, bromine, and iodine are assigned -1 unless paired with fluorine or oxygen
I think that's all of them. A lot of the rules are usually grouped together. I was just trying to be as clear as possible.
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104922499 1F
- Posts: 53
- Joined: Fri Sep 29, 2017 7:04 am
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soniatripathy
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Re: Oxidation state
I found that this video is pretty comprehensive (and shorter than the other response) and gives you the most used rules of assigning oxidation numbers: https://www.youtube.com/watch?v=-a2ckxhfDjQ&t=61s
Hopefully this helps!
Hopefully this helps!
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Rachel Wang
- Posts: 49
- Joined: Fri Sep 29, 2017 7:04 am
Re: Oxidation state
104922499 1F wrote:why is O3's oxidation state 0?
It's a triatomic gas with the same element -> no oxidation state
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Seth_Evasco1L
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