Module 5.3

Question 1

State the difference between a d-block element and a transition element.

Answer 1

A d-block element is one in which electrons are filling d-orbitals and the highest energy sub-shell is a d-sub-shell.
A transition element is a d-block element which forms at least one ion with an incomplete/partially filled d-sub-shell/d-orbital.

Question 2

State 3 properties of the transition elements.

Answer 2

1. Form coloured compounds.
2. Form compounds in which the transition element has different oxidation states.
3. Transition elements and their compounds can be used as catalysts.

Question 3

What is meant by the term ‘coordination number’?

Answer 3

The coordination number is the total number of coordinate bonds formed between the central metal ion and any ligands.

Question 4

What is a ligand?

Answer 4

A ligand is a molecule or ion that donates a pair of electrons to the transition metal ion to form a coordinate bond.

Question 5

What is a complex ion?

Answer 5

A complex ion is a transition metal ion bonded to one or more ligands by coordinate bonds (dative covalent bonds).

Question 6

Describe the role of cis-platin as a medicine

Answer 6

Cis-platin works by forming a platinum complex inside of a cell which binds to DNA and prevents the DNA of the cell from replicating. Activation of the cell’s own repair mechanism eventually leads to apoptosis, or systematic cell death.

Question 7

Explain using ligand substitutions:
* how haemoglobin transports oxygen around the body
* why carbon monoxide is toxic.

Answer 7

O2 coordinately bonds with Fe2+/Fe(II)/Iron
When required O2 is replaced by H2O OR CO2 OR O2 is replaced by CO OR H2O OR CO2 is replaced by O2
CO forms stronger bonds than O2.