5.3.1 Transition Elements

Question 1

Define a transition element

Answer 1

A d block element that forms at least one stable ion with partially filled d subshell

Question 2

Where are the transition metals located in the periodic table?

Answer 2

In the middle block from Ti to Cu

Question 3

What are the 2 elements in d block that are not considered as transition metals?

Answer 3

Scandium and zinc

Question 4

Why is scandium and zinc not considered as transition metals?

Answer 4

Scandium only forms Sc³⁺, where the d orbitals are empty

Zinc only forms Zn²⁺ where the d orbitals are full

Question 5

What is the noble gas configuration of chromium?

Answer 5

[Ar] 4s¹ 3d⁵

Question 6

What is the noble gas configuration of copper?

Answer 6

[Ar] 4s¹ 3d¹⁰

Question 7

Which electrons do transition metals lose first when forming ions?

Answer 7

4s

Question 8

What are some characteristic physical properties of transition metals?

Answer 8

• Metallic
• High density
• High melting and boiling point
• Shiny
• Good conductor of heat and electricity

Question 9

What are the characteristic chemical properties of transition metals?

Answer 9

• Variable oxidation states
• Coloured compounds/ions in solution
• Good catalysts
• Form complex ions

Question 10

In potassium manganate (VII), what is the oxidation number of Mn?

Answer 10

Mn = +7

Question 11

What are the 2 main ways in which transition metals act as an effective catalyst?

Answer 11

• They provide a surface on which reaction can take place
• They change oxidation states to form intermediates required for pathways with lower activation energy

Question 12

Give some examples of transition metal catalysts and the processes/reactions they catalyse?

Answer 12

• Iron (Haber process)
• Vanadium (V) oxide - contact process
• Nickel - hydrogenation of alkenes
• Manganese (IV) oxide - decomposition of hydrogen peroxide
• Copper sulfate - hydrogen production

Question 13

What is a complex ion?

Answer 13

Transition metal ion bonded to one or more ligands by coordinate bonds

Question 14

Define a ligand

Answer 14

Molecule or an ion that can donate a pair of electrons to the metals to form a coordinate bond

Question 15

What is a coordinate bond?

Answer 15

A bond in which one of the atom provides both the electrons required for bonding, also known as dative bonding

Question 16

What does the coordination number indicate?

Answer 16

The number of coordination bonds formed between the metal ion and its ligands

Question 17

What is a mono/unidentate ligand?

Answer 17

A ligand that forms one co-ordinate bond to the central metal ion
(one lone pair to donate)

Question 18

What is a bidentate ligand?

Answer 18

A ligand that forms two co-ordinate bonds to the central metal ion
(2 lone pairs to donate)

Question 19

What is a multidentate ligand?

Answer 19

A ligand that forms three or more co-ordinate bonds to the central metal ion

Question 20

Give some examples of common monodentate ligands

Answer 20

Cl⁻, H₂O, NH₃, CN⁻

Question 21

Name the most common bidentate ligand

Answer 21

ethane- 1.2- diamine
en

Question 22

How many coordinate bonds does EDTA⁴⁻ form?

Answer 22

six

Question 23

What ion is usually formed when a transition metal compound is dissolved in water? What shape is it?

Answer 23

Aqua ion, 6 H₂O ligands around the central metal ion.
Octahedral complex ion is formed

Question 24

If a. transition metal ion has 2 ligands, what shape is it usually?

Answer 24

Linear

Question 25

If a transition metal has 4 ligands, what shape is it usually?

Answer 25

Tetrahedral

Question 26

Name an exception to the general. rule that ions with 4 ligands is generally. tetrahedral. What shape is it?

Answer 26

Platin is square planar
forms cisplatin

Question 27

What shape is a complex ion if it has 6 ligands?

Answer 27

Octahedral

Question 28

How can complex ions display EZ or cis-trans isomerism?
What shapes of ions does this apply to?

Answer 28

Ligands differ in the way in which they are arranged in space 2 ligands of the same type can be on the same side of the metal ion (next to eachother), which forms. the. E or cis isomer 2 ligands of the same type can. be on. opposite sides of the metal ion (not next to eachother), which forms the Z or trans isomer. Applies to square planar and octahedral complex ions

Question 29

What conditions are needed for a complex ion to display optical isomerism?

Answer 29

Usually applies to octahedral molecules with 2 or more bidentate ligands, so that the mirror images are non-superimposable

Question 30

What is cis-platin used for? Describe its mechanism of action

Answer 30

It is used as an anti cancer drug
It binds to DNA of fast growing cancer cells and prevents cell division, hence reducing the growth of cancer

Question 31

Which metal ion is present in haem group?

Answer 31

Fe²⁺

Question 32

What is the coordination number of a haem group?

Answer 32

6

Question 33

What are the ligands in haem group?

Answer 33

4 nitrogen forming the porphyrin ring
1 oxygen
1 globin

Question 34

Why is CO toxic?

Answer 34

CO also coordinately bonds. to the Fe²⁺, and bonds more strongly to Fe²⁺ than O₂. Stops O₂ from bonding to haemoglobin, so O₂ cannot be transported around the body