How many 3d series elements ( Sc to Zn ) have positive standard potential for `M^(+2)`/M?

Four successive members of the first series of the transition metals are listed below. For which one of them the standard potential (E_(M^(2+)//M)^(@)) value has a positive sign?

Four successive members of the first series of transition metals are listed below. For which one of the of standard potential (E_(M^(2+)//M)^(@)) value has a positive sign ?

In 3d series which element have highest IE_(3) ?

Which of the following elements have low value of E^(Theta) (Electrode potential) for M^(+3)//M^(+2) conversion