Transition Metals

Question 1

What is a transition metal?

Answer 1

A transition metal is an element with a partially filled d orbital OR
It is a metal which forms an ion with a partially filled d orbital.

Question 2

State some properties of transition metals

Answer 2

• They are hard and have high densities
• They have high melting and boiling points
• The form compounds in which they exhibit a variety of oxidation states
• They form coloured compounds and ions
• They and their compounds often show catalytic activity
• They are often paramagnetic rather than diamagnetic
• They show great tendency to form stable complexes

Question 3

State the colours that correspond to the different oxidation states of vanadium

Answer 3

Oxidation State: +5
Colour: yellow
Ion: VO2+
Name: Dioxovanadium (V) ion

Oxidation State: +4
Colour: blue
Ion: VO2+
Name: Oxovanadium (IV) ion

Oxidation State: +3
Colour: green
Ion: V3+
Name: Vanadium (III) ion

Oxidation State: +2
Colour: violet
Ion: V2+
Name: Vanadium (II) ion

Question 4

When is a species said to be diamagnetic?

Answer 4

When they are repelled from a magnetic field. Repulsion occurs because all the electrons are safely paired eg. Calcium

Question 5

When is a species said to be paramagnetic?

Answer 5

When it is attracted by a magnetic field. This attraction occurs when there are unpaired electrons

Question 6

When is a complex formed?

Answer 6

A complex is formed when a central atom (usually a transition element) is combined with surrounding ions or molecules called ligands

Question 7

What does the overall charge of a complex depend on?

Answer 7

This depends on the charge of both the central atom and the surrounding ligands

Question 8

What is the coordination number?

Answer 8

This is the number of ligands in a complex

Question 9

State the shapes assigned for the three different coordinate numbers in complexes

Answer 9

• 2: linear
• 4: tetrahedral or square planar
• 6: octahedral

Question 10

What conditions should be met for something to be considered a ligand?

Answer 10

• a species must have at least one lone pair of electrons

Question 11

What is a ligand?

Answer 11

A ligand is any atom or molecule attached to a central atom in a complex

Question 12

What are the colours of some common complexes?

Answer 12

[Fe(H2O)6]2+ = green 
[Co(H2O)6]2+ = pink 
[Cu(H2O)6]2+ = pale blue
[Fe(H2O)6]3+ = violet 
[Cr(H2O)6]3+ = ruby red

[Co(NH3)6]2+ = straw coloured 
[Cu(NH3)6]2+ = dark blue 
[CoCl4]2- = blue
[CuCl4]2- = yellow

Question 13

Draw the different shapes for the coordination numbers

Answer 13

Yes, you have to do it. Page 246 and beyond

Question 14

Use the ligand exchange theory to explain how the presence of carbon monoxide in the blood can prevent oxygen from reaching the tissues

Answer 14

Oxygen is transported to the tissues as a complex with the haemoglobin found in the red blood cells.

CO can also form a complex with haemoglobin

The stability for the haemoglobin- CO complex is much higher than that of the haemoglobin-O2 complex, so CO successfully competed with oxygen.

Therefore the presence of CO can prevent O2 from reaching the tissues