Chapter 23 - The Transition Metals

Which of the following are typical properties of a Transition Metal element?

Which of the following is the correct electron configuration of Copper (Cu)?

When ions are formed from transition metal elements, the 4s electrons are lost first.

The formal definition of a transition element: An [blank_start]element[blank_end] which forms at least one [blank_start]stable[blank_end] ion with a [blank_start]partially-filled[blank_end] [blank_start]d-shell[blank_end] of electrons.

Scandium and Zinc are both d-block and transition metal elements

Match each definition to the correct term. Multiple labels may be required to complete each definition (some were too long).

Only transition metals are able to form complexes.

How would you classify the following ligands?

What is the shape of this complex ion?

What is the shape of this complex ion?

Complex ions with multidentate ligands are called [blank_start]chelates[blank_end]. Chelates can be used to effectively remove [blank_start]d-block[blank_end] metal ions from solution. If you add a hexadentate ligand such as [blank_start]EDTA[blank_end] to a solution of a transition metal salt, the EDTA will replace all six water [blank_start]ligands[blank_end] in the aqua ion, for example: [Cu(H2O)6](2+) + EDTA(4-) --> [CuEDTA](2-) + 6H2O In this equation, [blank_start]two[blank_end] species are replaced by [blank_start]seven[blank_end]. This increase in the number of particles causes a significant increase in [blank_start]entropy[blank_end] which drives the reaction to the right. for this reason chelate complexes with [blank_start]polydentate[blank_end] ligands are favoured over complexes with [blank_start]monodentate[blank_end] ligands. This is known as the chelate effect.

Optical isomerism occurs in transition metal complexes when there are two or more bidentate ligands.

Geometric isomerism occurs in transition metal complexes which are octahedral or tetrahedral in shape.

When the ligands bond with the transition metal ion, there is [blank_start]repulsion[blank_end] between the electrons in the ligands and the electrons in the d orbitals of the [blank_start]metal ion[blank_end]. That raises the energy of the d orbitals. However, because of the way the d orbitals are arranged [blank_start]in space[blank_end], it doesn't raise all their energies by the same amount. Instead, it splits them into [blank_start]two groups[blank_end], one group of 2 orbitals with a slightly [blank_start]higher[blank_end] energy level than the other 3. The size of the energy gap between them varies with the nature of the transition metal ion, its [blank_start]oxidation state[blank_end] (whether it is 3+ or 2+, for example), and the nature of the [blank_start]ligands[blank_end]. When [blank_start]white light[blank_end] is passed through a [blank_start]solution[blank_end] of this ion, some of the energy in the light is used to [blank_start]promote[blank_end] an electron from the lower set of orbitals into a space in the upper set. The amount of energy absorbed in order to promote this electron corresponds to a [blank_start]wavelength[blank_end] of the visible light. We therefore see a combination of the other colours in the spectrum, which often shows as the [blank_start]complementary[blank_end] colour of the one absorbed.

Why can transition metals form ions with variable oxidation states?

Which two transition metals are found in the catalytic converters of modern cars?

A heterogenous catalyst is in the same phase as the reactants.

What can be done to minimise the costs of using heterogenous catalysts?

Catalysts will eventually cease to work.

When the catalyst is in the same phase as the reactant, an intermediate species is formed.

What is autocatalysis?