Iron has oxidation state of -2, in the Tetracarbonyl Ferrate ion
Zinc commonly exists in compounds in the +2 oxidation state only, and as a metal with an oxidation state of 0.0, 1 and 2 oxidation states
The oxidation state of oxygen in alkaline earth metal oxides is -2. Alkaline earth metals always have a +2 oxidation state, which means oxygen has to have a -2 oxidation state to balance the charges in the compound.
There are no such metals whose common oxidation state is -2
No, Pb is not a transition metal and it has 2 oxidation states
Zinc is in oxidation state +2 and oxygen in oxidation state -2. Zinc Oxide itself has not net charge/oxidation state.
When the metal can exist in more than one oxidation state
A pure metal has the oxidation state zero.
The oxidation state of sodium (Na) in Na2C2O4 is +1 because it is an alkali metal. The oxidation state of carbon (C) in C2O4^2- (oxalate ion) is +3.
Oxidation number of Li is +1. Oxidation number of oxygen is -2.
Barium in group 2 has just two oxidation numbers, 0 in the metal, +2 in its compounds.
The oxidation state is 1.
The subscript of the second ion identifies the oxidation state of the transition metal