If so, how can you find them? I feel so dumb right now! I love Chemistry to death but I was absent 3 days last week while we learned this and I have a test tomorrow! Please help if you can! I know the other oxidation numbers except for the transition metals! Thank you all! :o)
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well there are rules that you have to follow and most of the elements differ everytime they are combined with different elements.
the thing you MUST do FIRST is look for any H's, O's, or F's in the equation
1)any element just by itself not in a compound, their oxidation number is 0
ex: H2's oxidation number is 0
ex: Ag: oxidation number is 0 if its just something like Ag + BLA = LALA
2) the oxidation number of H is always +1, unless its just by itself (see #1)
3) the oxidation number of O is always -2, unless its just by itself (see #1)
4) the oxidation number of F is always -1, unless its just by itself (see#1)
ok so after you have written those oxidation numbers in rules 1-4 over each H, F, or O atom in the compound, you can look at the elements that we havent talked about yet
for example::::
N2O4
the oxidation number of O is -2.
since there are 4 O's, the charge is -8. now remember that N2O4 has to be neutral so the N2 must have a charge of +8
+8 divided by 2 = +4
N has an oxidation number of +4.
more rules:
5) the sum of oxidation numbers in a compound add up to 0 (when multiplied by the subscripts!!!) (see above example)
6) the sum of oxidation numbers in a polyatomic ion is the charge (for example, PO4 has a charge of (-3) so
oxidation # of O = -2. (there are 4 O's = -8 charge on that side ) P must have an oxidation number of 5. (-8+5= -3), and -3 is the total charge of the polyatomic ion.
THESE ARE VERY SIMPLE RULES THAT YOU HAVE TO REMEMBER. the stuff everyone else is talking about like the group 1 and etc, column 1 or 7, they're just talking about the charges. make sure that you don't listen to them, because other than H, F, and O, most of the elements in their compounds DO NOT have their charge as their oxidation number. in the first example N2O2, N's charge is -3 according to the periodic table, but in the example it turned out to be +4. CHARGES are misleading!
the thing you MUST do FIRST is look for any H's, O's, or F's in the equation
1)any element just by itself not in a compound, their oxidation number is 0
ex: H2's oxidation number is 0
ex: Ag: oxidation number is 0 if its just something like Ag + BLA = LALA
2) the oxidation number of H is always +1, unless its just by itself (see #1)
3) the oxidation number of O is always -2, unless its just by itself (see #1)
4) the oxidation number of F is always -1, unless its just by itself (see#1)
ok so after you have written those oxidation numbers in rules 1-4 over each H, F, or O atom in the compound, you can look at the elements that we havent talked about yet
for example::::
N2O4
the oxidation number of O is -2.
since there are 4 O's, the charge is -8. now remember that N2O4 has to be neutral so the N2 must have a charge of +8
+8 divided by 2 = +4
N has an oxidation number of +4.
more rules:
5) the sum of oxidation numbers in a compound add up to 0 (when multiplied by the subscripts!!!) (see above example)
6) the sum of oxidation numbers in a polyatomic ion is the charge (for example, PO4 has a charge of (-3) so
oxidation # of O = -2. (there are 4 O's = -8 charge on that side ) P must have an oxidation number of 5. (-8+5= -3), and -3 is the total charge of the polyatomic ion.
THESE ARE VERY SIMPLE RULES THAT YOU HAVE TO REMEMBER. the stuff everyone else is talking about like the group 1 and etc, column 1 or 7, they're just talking about the charges. make sure that you don't listen to them, because other than H, F, and O, most of the elements in their compounds DO NOT have their charge as their oxidation number. in the first example N2O2, N's charge is -3 according to the periodic table, but in the example it turned out to be +4. CHARGES are misleading!
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Yes they have oxidation numbers, but because of their more complex electron configurations, they will have more oxidation states than the other elements. Usually look up a table for these sorts of things, or if you're given a compound containing transition metals, use what you know about the other elements in the compound to find the oxidation state of the transition metal.