Transition Metals

Question 1

Which block are transition metals in?

Answer 1

D-block

Question 2

Which elements are in the d-block?

Answer 2

Titanium to copper

Question 3

Which elements in the d-block have the highest energy?

Answer 3

The elements in the first row of the d-block have the highest energy in 4s and 3d subshells.

Question 4

How do you work out the electron configuration of an element?

Answer 4

You find the total number of 4s and 3d electrons by subtracting 18 from the atomic number.

Question 5

Which shell is always filled first (before the 3d subshell)?

Answer 5

The 4s subshell.

Question 6

In which other way can you show subshell configuration?

Answer 6

Subshell notation.

Question 7

Which two d-block elements are not transition metals?

Answer 7

Scandium and zinc are not transition metals.

Question 8

What is the definition of a transition metal?

Answer 8

A transition metal is one that can form an ion with a partially filled d-subshell.

Question 9

How many electrons can a d-orbital hold?

Answer 9

A d-orbital can hold up to 10 electrons.

Question 10

What must a transition metal have to be a transition metal?

Answer 10

The ability to form an ion with between 1 and 9 electrons in its d-subshell.

Question 11

Why is zinc not a transition metal?

Answer 11

Zinc is not a transition metal because it can only form one ion - Zn 2+ - which has a full d-subshell and an empty 4s subshell.

Question 12

Why is scandium not a transition metal?

Answer 12

Scandium is not a transition metal because it can only form one ion - Sc 3+ - which has an empty d-subshell as well as an empty 4s subshell.

Question 13

Which electrons are removed first from ions?

Answer 13

Electrons in the 4s subshell are removed first.

Question 14

What type of charge does a transition metal ion carry?

Answer 14

A positive charge.

Question 15

What provides evidence for electron configurations?

Answer 15

Ionisation energies provide evidence for ionisation energies.
The first ionisation energy is roughly the same from Scandium to Copper. This means that they all have a similar structure and lose the first electron from the same shell.
The second ionisation energy increases steadily across the elements. Chromium and Copper are slightly higher than you would expect. This shows that the electron is taken from even closer to the nucleus.
The third ionisation energy also increases steadily but with a step down in ionisation energy at Iron. This is because from iron onwards, the electrons are removed from a filled paired d-subshell.

Question 16

Why is it easier to remove an electron in a paired 3d-orbital?

Answer 16

When there are two electrons in the same orbital, they repel each other slightly, and so it is easier to remove one of them.

Question 17

What special chemical properties do transition metals have?

Answer 17

They can form complex ions
They form coloured ions in solution
They act as good catalysts
They exist in various oxidation states

Question 18

What electron configuration does Copper prefer?

Answer 18

Copper prefers to have one electron in its 4s subshell and a full 3d subshell.

Question 19

What is a complex ion?

Answer 19

A complex ion is a metal ion surrounded by dative covalently bonded ligands.

Question 20

What is a dative covalent bond?

Answer 20

A dative covalent bond is one in which both of the electrons donated come from the same pair.

Question 21

What is a ligand?

Answer 21

A ligand is an atom, molecule or ion that donates a pair pf electrons to a central metal ion.

Question 22

What is the coordination number?

Answer 22

The coordination number is the number of dative covalent bonds that are formed with the central metal ion.

Question 23

What is ligand substitution?

Answer 23

Ligand substitution is whereby the place of one ligand can be swapped for another.

Question 24

What does ligand exchange do to a compound?

Answer 24

Ligand exchange almost always changes the colour of the solution.

Question 25

What do 6 dative covalent bonds mean about the shape of the complex ion?

Answer 25

It means that the complex ion will have an octahedral shape.

Question 26

What do 4 dative covalent bonds mean about the shape of the complex ion?

Answer 26

It means that the complex ion will have an tetrahedral shape.

Question 27

What do 2 dative covalent bonds mean about the shape of the complex ion?

Answer 27

It means that the complex ion will have an linear shape.

Question 28

What is the overall charge on a complex ion known as?

Answer 28

The overall charge on complex ion is known as the oxidation state.

Question 29

How do you work out the overall oxidation state of the metal in a complex ion?

Answer 29

Oxidation state of the metal ion =

Total oxidation state - sum of oxidation states in ligands

Question 30

How do ligands form bonds?

Answer 30

Ligands form bonds by using lone pairs of electrons.

Question 31

What can ligands do with each other?

Answer 31

Ligands can exchange places with one another.

Question 32

What happens to the coordination number if the ligands are the same size as each other?

Answer 32

The coordination number stays the same, as does the shape of the complex ion.

Question 33

What happens to the coordination number if the ligands different sizes to each other?

Answer 33

There will be a change in the coordination number and a change in the shape of the complex ion.

Question 34

Is the subsitution always complete?

Answer 34

No, sometimes the substitution is partial.

Question 35

When can ligand exchanges be reversed?

Answer 35

Ligand exchanges can be reversed when the new complex ion is much more stable than the last one.
If the new ligand forms stronger bonds with the central metal ion than the previous metal ion, the ligand exchange cannot be reversed.

Question 36

What is the effect of adding alkali to metal aqua-ions?

Answer 36

Adding alkali to metal aqua-ions can form precipitates.

Question 37

Are the metal hydroxides soluble?

Answer 37

No, the metal hydroxides are insoluble.

Question 38

What happens to the entropy of the system if a bidentate ligand replaces a monodentate ligand?

Answer 38

If a monodentate ligand is replaced by a bidentate ligand, the entropy of the system increases as there are more product molecules involved than reactant molecules. This means the total entropy change for the reaction is likely to be positive.

Question 39

Ligands with one lone pair are called…

Answer 39

…monodentate.

Question 40

Ligands with two lone pairs are called…

Answer 40

…bidentate.

Question 41

How many dative covalent bonds can bidentate ligands form?

Answer 41

Bidentate ligands can form two dative covalent bonds with the metal ion.

Question 42

Ligands with more than two lone pairs are called…

Answer 42

…polydentate.

Question 43

How is colour created?

Answer 43

The 3d subshell splits into two energy levels. Electrons tend to occupy the lower energy level but they can jump up to higher energy levels by absorbing wavelengths of light, equal to the energy gap.

Question 44

What does the frequency absorb depend upon?

Answer 44

The frequency absorbed depends on the energy gap.

Question 45

What happens to the rest of the frequencies that aren’t absorbed?

Answer 45

Any frequencies that aren’t absorbed are transmitted, which means that the colour you see are the frequencies that aren’t absorbed.

Question 46

What can affect the colour of the metal ion?

Answer 46

The colour can be affected by the central metal ion, the ligands and the coordination number.