Organic Chemistry 2A1

What is a cation?

Explain what a transitional metal is and give examples

What is a complex ion?

What is a ligand?

What is a Coordination Number?

Give examples of common ligands

H2O (aqua), NH3 (amino)—neutral. Cl- (chloro), OH- (hydroxy)—anions.

Explain how copper sulphate becomes hexaaquacopper (ii) ion

Copper sulphate is a white anyhydrous solid in its pure form. When water is added, a powerful exothermic reaction occurs forming hexaaquacopper (ii) ion. CuSO4 (s) + 6H2O (l)—→ [Cu(H2O)6] (aq) + SO4²- (aq)

Explain what unidentate, bidentate, multidentate ligands and chelates are

Unidentate ligands only have one available lone pair to coordinately bond with a metal while bidentates only have 2 and multidentates have multiple (EDTA^4- has 6 lone pairs available). When a multidentate ligand forms a complex with a metal ion are called chelates. Which are more stable than unidentate because it there is an increased entropy which makes it more stable

What are the shapes of complex ions?

The octahedral shape is when 6 ligands are bonded to the metal ion giving it a coordination number of 6. The tetrahedral is when 4 ligands are bonded to the metal ion giving it a coordination number of 4. In some cases, the coordination number of 4 can make the shape square planar. Lastly, if the coordination number is 2, it makes a linear shape. This is common with silver and copper ions

Why is there a change in the colour of complexes?

Colour is associated with incomplete d-sub shells in transition metals so those with complete d-sub shells are colourless. Example; Cu (I) and Ag (I). It’s usually because there was a change in either oxidation state, type of ligand involved or the number of ligands bonded

How are colour changes measured?

Using a colorimeter, wave lengths pass through the solution, and