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).