Transition Metals

Question 1

Definition of transition metal

Answer 1

A metal that can form one or more stable ions with a partially filled d sub-level.

Question 2

Elements in the d block that are not transition metals and why

Answer 2

• Zinc - only forms one ion Zn 2+ which has a full d sub-level
• Scandium - Only form one ion Sc 3+, which has an empty d sub-level

Question 3

What properties do all transition metals have?

Answer 3

1. They all have a high density
2. They all have high melting and boiling point
3. Their ionic radii are the same

Question 4

Special chemical properties of transition metals

Answer 4

1. They can form complex ions
2. They form coloured ions
3. They are good catalysts
4. They can exist in variable oxidation states

Question 5

What is a complex ion?

Answer 5

A complex is a central metal atom or ion surrounded by coordinately bonded ligands.

Question 6

What is a coordinate bond?

Answer 6

A covalent bond in which both electrons in the share pair come from the same atom.

Question 7

What is a ligand?

Answer 7

A ligand is an atom, ion or molecule that donates a pair of electrons to a central transition metal ion to form a coordinate bond.

Question 8

What is the coordination number of Cl-?

Answer 8

4 - (too big to form 6)

Question 9

Equation for oxidation sate of the metal

Answer 9

total oxidation state - the sum of the oxidation states of the ligands

Question 10

Types of ligands and examples

Answer 10

• monodentate (H2O, NH3, Cl-)
• Bidentate (ethanediamine, ethanedioate)
• multidentate (EDTA)

Question 11

Equation for energy gap

Answer 11

ΔE = hv = hc/λ

v= frequency of light absorbed (Hz)
h = Planck’s constant (6.63x10-34 J s)
c = speed of light (3.00 x 10^8 m s-1)
λ = wavelength of light absorbed (m)

Question 12

What effects the size of the energy gap?

Answer 12

• oxidation state
• central metal ion
• ligands
• coordination number

Question 13

What happens when visible light hits a transition metal ion?

Answer 13

• Some light frequencies are absorbed when electrons jump up to the higher orbitals. The frequencies absorbed depend on the size of the energy gap.
• The rest of the frequencies are transmitted or reflected. The reflected frequencies combine to make the complement of the colour of the absorbed frequencies.

Question 14

How does spectroscopy work?

Answer 14

1. White light is shone through a filter, which is chosen to only let though the colour of light that is absorbed by the sample.
2. The light passes through the sample to a colorimeter, which calculates how much light was absorbed by the sample.
3. The more concentrated a coloured solution is, the more light it will absorb. This is then used to find out the concentration of the solution of transition metal ions.

Question 15

Vanadium colours oxidation states and formula

Answer 15

VO2+ (2ox) +5 Yellow
VO +2 (1ox) +4 Blue
V3+ +3 Green
V2+ +2 Violet

Question 16

Redox Titrations equations
Ethane dioate and manganate

Answer 16

C2O4 —-> CO2
MnO4 —> Mn2+
Fe2+ <—> Fe3+

Question 17

Generally, what can be used to reduce a transition metal

Answer 17

Zn and H2SO4

Question 18

Colour of MnO4

Answer 18

Purple

Question 19

Which two ligands can result in optical isomerism

Answer 19

Ethylenediamine
C2O4-

Question 20

General equation of metal complex reacting with Chloride ions

Answer 20

[M(H2O)6]2+ + 4Cl —–> [M(Cl)4]2- + 6H2O

Question 21

Reagents used to reduce vanadium

Answer 21

Zn and H2SO4

Question 22

Colour and structure of [Co(H2O)6]2+

Answer 22

Octahedral Pink

Question 23

Colour and structure of [Co(NH3)6]2+

Answer 23

Octahedral straw coloured

Question 24

Colour and structure of [CoCl4]2-

Answer 24

Tetrahedral blue

Question 25

Colour ansd structure of [CuCl4]2-

Answer 25

Tetrahedral yellow

Question 26

Colour and structure of [Fe(H2O)6]3+

Answer 26

Octahedral purple

Question 27

Colour and structure of [FeCl4]-

Answer 27

Tetrahedral yellow

Question 28

Haem in haemoglobin

Answer 28

Iron (II) complex with a multidentate ligand (4 nitrogens) (Porphyrin)

Question 29

Where do other 2 bonds come from in haemoglobin

Answer 29

Protein globin and oxygen/water molecule

Question 30

Explain how haemoglobin picks up water molecule

Answer 30

In areas of high O2 concerntration- O2 substitutes in for water- oxyhaemoglobin In areas of low O2 concerntration- H2O subs in for O2

Question 31

Explain why complex metal ions are acidic in solution

Answer 31

They have a high charge to size ratio This weakens the OH bonds on the water molecules More H+ ions are released into solution Decreasing the PH

Question 32

What is a chealating ligand

Answer 32

A ligand that forms more than one coordinate covalent bond with central metal ion

Question 33

Why does a ligand sub reaction aways happen when EDTA is present

Answer 33

EDTA binds more tightly to central ion- Has a chealating effect Complex formed is more stable

Question 34

Draw isomers of...

Answer 34

Question 35

Answer 35

Anti-Cancer drug

Question 35

Answer 35

Anti-Cancer drug

Question 36

Explain why different ligands on same central metal ion results in different colour of solution

Answer 36

D orbitals will have different energies Light energy will be absorbed Different wavelengths of light will be absorbed

Question 37

Role of iron in haemoglobin

Answer 37

Oxygen forms a coordinate bond with iron in haemoglobin

Question 38

Why does carbon monoxide cause death? (describe in terms of transition metals)

Answer 38

Carbon monoxide binds more strongly to iron than oxygen More stable complex is formed Prevents oxygen from being transported

Question 39

Structure of ethanedioate

Answer 39