Определить валентность элементов в оксидах -AL2O3,FeO,Fe2O3,Cr2O3,CrO3,SO2,SO3, P2O5,MnO2,Mn2O3,Mn2O7,NO,N2O5,Ag2O,Na2O.
Al2(III)O3(II),
Fe(II)O(II),
Fe2(III)O3(II),
Cr2(III)O3(II),
Cr(VI)O3(II),
S(IV)O2(II),
S(VI)O3(II),
P2(V)O5(II),
Mn(IV)O2(II),
Mn2(III)O3(II),
Mn2(VII)O7(II),
N(II)O(II),
N2(V)O5(II),
Ag2(I)O(II),
Na2(I)O(II).