Transition Metals Flashcards

1
Q

What block are transition metals?

A

d-block

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2
Q

Why do certain characteristics occur within transition metals?

A

Due to an incomplete d-sub level in their atoms or ions

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3
Q

What characteristic properties are associated with transition metals?

A
  • complex formation
  • formation of coloured ions
  • variable oxidation states
  • catalytic activity
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4
Q

What is a ligand?

A

A molecule or ion that forms a co-ordinate bond with a transition metal by donating a pair of electrons

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5
Q

Describe the complex that transition metals form?

A

A central metal atom or ion surrounded by ligands

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6
Q

What is the co-ordination number?

A

The number of co-ordinate bonds to a central atom or ion.

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7
Q

What is a lewis base?

A

Lone pair donor

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8
Q

What is a lewis acid?

A

Lone pair acceptor

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9
Q

Give examples of 3 monodentate ligands

A

H₂O, NH₃ and Cl-

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10
Q

Which monodentate ligands are uncharged?

A

H₂O and NH₃

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11
Q

Which transition metal undergoes incomplete substitution reactions?

A

Copper forms [Cu(NH₃)₄(H₂O)₂]²⁺

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12
Q

Why does Cl- form 4 co-ordinate bonds instead of 6?

A

Because it is larger than the other uncharged ligands

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13
Q

Give three factors that cause ΔE to change

A
  • Co-ordination number
  • Ligand
  • Oxidation state
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14
Q

Give two examples of bidentate ligands

A
  • ethane-1,2-diamine

- ethanedioate

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15
Q

What are bidentate ligands?

A

Form two co-ordinate bonds and donate two electron pairs

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16
Q

Give two examples of multidentate ligands?

A
  • EDTA⁴⁻

- Haemoglobin

17
Q

What are the uses of EDTA⁴⁻?

A
  • an antidote for metal poisoning, removes it from blood

- anticoagulant, removes Ca²⁺ and prevents blood from clotting

18
Q

What is chelation?

A

Entropically driven reaction because there are moles on the right side of the arrow. The enthalpy change is close to 0 because you are breaking and forming the same number of bonds.

19
Q

Which transition metal ion is found in haem?

A

Fe²⁺

20
Q

What co-ordinate bonds are formed in haemoglobin?

A
  • 4 to a porphyrin rig
  • 5th to globin protein
  • 6th to oxygen (or carbon monoxide)
21
Q

What is the common shape that transition metal complexes form?

A

Octahedral

22
Q

What types of isomerism that transition metal complexes form and when does this happen?

A
  • Cis-trans: monodentate ligands

- Optical: bidentate ligands

23
Q

What shape do transition metal complexes form with Cl-?

A

Tetrahedral

24
Q

What type of shape shows cis-trans isomerism?

A

Square planar

25
Q

What silver complex is used in Tollens reagent?

A

[Ag(NH₃)₂]⁺

26
Q

Why are transition metals coloured?

A

Colour arises when some wavelengths of light of visible light are absorbed and the remaining wavelengths are reflected.
d electrons are excited from ground level when light is absorbed

27
Q

What is the equation for the energy change when d electrons are excited?

A

∆E = hν = hc/λ

28
Q

Outline an experiment to determine the concentration of a solution with a colorimeter.

A
  • Add a ligand to intesify the colour
  • Make up solutions of known concentrations
  • Measure absorption
  • Plot results on a graph and draw a curve of best fit
  • Measure unknown absorption and compare on calibration curve
29
Q

What are the colours of vanadium species in different oxidation states?

A
V²⁺= purple
V³⁺= green
VO²⁺= blue
VO₂⁺= yellow
30
Q

What can be used to reduce species of vanadium?

A

Zinc with sulphuric acid. Hydrochloric acid can’t be used because it could be oxidised to toxic chlorine gas

31
Q

Redox titration equation of Fe²⁺ and MnO₄⁻

A

5Fe²⁺ + MnO₄⁻ + 8H⁺ –> Mn²⁺ + 4H₂O + 5Fe³⁺

32
Q

Redrox titration equation of MnO₄⁻ and C₂O₄²⁻

A

2MnO₄⁻ +16H⁺ + 5C₂O₄²⁻ –> 2Mn²⁺ + 8H₂O + 10CO₂

33
Q

Explain why iron(III) ions are more acidic than iron(II) ions

A
  • [Fe(H₂O)₆]³⁺ → [Fe(H₂O)₅(OH)]²⁺ + H⁺
  • Fe³⁺ ion has higher charge density than Fe²⁺
  • weakens O–H bond