For each of the compounds or ions contained in this table, show the correct oxidation state (oxidation number) for each element.  Remember that common ions have the oxidation state corresponding to their charge.  

K2CrO4	K = +1; Cr = +6; O = -2	Al(OH)3	Al = +3; O = -2; H = +1
Pb	Pb = 0	IO3-	I = +5; O = -2
H3PO4	H = +1; P = +5; O = -2	SO3	S = +6; O = -2
PH3	P = -3; H = +1	Na2SO3	Na = +1; S = +4; O = -2
CaH2	Ca = +2; H = +1	Rb2SO4	Rb = +1; S = +6; O = -2
OF2	O = +1; F = -1	Fe2S3	Fe = +3; S = -2
CN-	C = +2; N = -3	Li2O	Li = +1; O = -2
NH4Br	N = -3; H = +1; Br = -1	CBr4	C = +4; Br = -1
AsO43-	As = +5; O = -2	N2	N = 0
Fe3+	Fe = +3	Fe3O4	Fe = +8/3; O = -2
XeO4	Xe = +8; O = -2	NaN3	Na = +1; N = -1/3
nickel(II) sulfate	Ni = +2; S = +6; O = -2	arsenic(II) nitrite	As = +2; N = +3; O = -2
tin(II) fluoride	Sn = +2; F = -1	lead(IV) sulfide	Pb = +4; S = -2

What is the highest oxidation state of carbon? +4

What is the highest oxidation state of sulfur? +6

What is the lowest common oxidation number of carbon? -4

What is the lowest common oxidation number of nitrogen? -3

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