Question

For the following five coordination complexes identify the correct oxidation state of the metal.


[Ni(CO)4]

cis−[PdCl2(P(CH3)3)2]

[Ir(NH3)3Cl3]

[Ru(NH3)6]Cl2

[Cr(en)2I2]I

Answer 1

You take these apart bit by bit. You know the compound has a charge of 0. You know the oxidation states must add to zero. For [Ni(CO)4] and call Ni = x, then
x + 4*0 = 0
x + 0 = 0 so
x = Ni = 0
[Ir(NH3)3Cl3]
Cl is -3 since each is -1. NH3 is zero and Ir = x so
x + 0 + (-3) = 0 and x = +3 = Ir
[Cr(en)2I2]I
x + 0 + (-2) + (-1) = 0
x = Cr = +3