Name the oxometal anions of the first series of the transition metals in which the metal exhibits the oxidation state equal to its group number.
[ScO2]−; Group number = Oxidation state of Sc = 3
[TiO3]2−; Group number = Oxidation state of Ti = 4
[VO3]−; Group number = Oxidation state of V = 5
[Cr2O7]2−; Group number = Oxidation state of Cr = 6
[CrO4]2−; Group number = Oxidation state of Cr = 6
[MnO4]−; Group number = Oxidation state of Mn = 7