This question is about complexes of transition metals.
State the meaning of the term co-ordination number of a complex ion.
The molecule H2OH_2OH2O commonly acts as a ligand in transition metal chemistry.
The electron pair repulsion theory can be used to predict the shape of a H2OH_2OH2O molecule. Draw the shape of a H2OH_2OH2O molecule. Include any lone pairs of electrons that influence the shape. Name the shape.
Nickel forms a complex with carbon monoxide, Ni(CO)4Ni(CO)_4Ni(CO)4. Suggest why the oxidation state of nickel is zero in this complex.
The compound [Co(NH3)4Cl2]NO3[Co(NH_3)_4Cl_2]NO_3[Co(NH3)4Cl2]NO3 contains ammonia ligands.
Deduce the oxidation state of cobalt in [Co(NH3)4Cl2]NO3[Co(NH_3)_4Cl_2]NO_3[Co(NH3)4Cl2]NO3.
Name the type of bond formed between the nitrogen atom of the ammonia ligand and the central cobalt ion in this complex.
The compound [Co(NH3)4Cl2]NO3[Co(NH_3)_4Cl_2]NO_3[Co(NH3)4Cl2]NO3 contains a complex ion that shows isomerism. One of its isomers is shown below:

Identify the isomer shown, draw the other isomer of the complex ion, and state the type of isomerism shown.
Complete the equation to show the formation of the hexaaquacobalt(II) complex from anhydrous cobalt(II) chloride: CoCl2+6H2O→CoCl_2 + 6H_2O \rightarrowCoCl2+6H2O→