1. Give an example (including the charges) of:

a) two complex ions that are geometrical isomers of each other.

b) two complex ions that are optical isomers of each other.

c) two complex ions that are coordination sphere isomers.

2. What is the oxidation number of the underlined atom in the following compounds:

a) CO₂

b) K₂Cr₂O₇

c) Fe(CN)₆ ^-4

3. The compound Co(NH₃)₅SO₄Br exists in a red form and a violet form. The red form reacts with silver ions to form AgBr but does not react with barium ions to form BaSO₄. The violet form does the opposite in that it does not react with silver ions but does react with barium ions to form BaSO₄.

a) Indicate the structures of the complex ions in each case. Label which is red and which is violet.

b) What is the coordination number of the Co?

c) What is the oxidation number of the Co?.