5.3.2 - Transition Metals. Flashcards

Definitions, Colours, Reactions and Complexes.

1
Q

What is the DEFINITION of a Transition Metal?

A

A d-block element which forms at least 1 ion with an incomplete d-orbital/ sub-shell.

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2
Q

Which 2 elements in the first row of the d-block have unusual electron configurations?

A
  • Chromium (4s1 3d5).
  • Copper (4s1 3d10).
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3
Q

Which 2 elements in the first row of the d-block are NOT transition elements?

A

Scandium (Sc) and Zinc (Zn) because they are not able to form at least 1 ion with an incomplete d-orbital/ sub-shell.

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4
Q

Why is the d-block called the “d-block”?

A

Because the highest energy electrons are in the d orbitals/sub-shell.

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5
Q

Give 3 chemical properties of transition elements and their compounds.

A
  • They can form multiple oxidation states.
  • They can form coloured compounds.
  • They can act as catalysts.
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6
Q

Give 3 physical properties of transition elements.

A
  • High Melting and Boiling Points.
  • They are malleable (can be shaped).
  • They are good conductors of heat and electricity.
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7
Q

What is the DEFINITION of a ligand.

A

A ligand is a species (molecule or ion) that can donate a pair of electrons to a central metal ion to form a coordinate/dative covalent bond.

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8
Q

What is the DEFINITION of a coordination number.

A

The amount of coordinate bonds which a metal ion forms in a complex ion.

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9
Q

What is the DEFINITION of a dative/ coodinate bond.

A

A covalent bond which has been formed where one of the bonded atoms has donated both electrons in its shared pair to a central metal ion in a complex ion.

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10
Q

What is the DEFINITION of a ligand substitution reaction.

A

A reaction where one ligand in a complex ion is substituted by another ligand.

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11
Q

What is the DEFINITION of a complex ion?

A

A transition metal ion bonded to one or more ligands by coordinate (dative covalent) bonds.

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12
Q

Give some examples of a neutral ligand.

A
  • Ammonia :NH3
  • Water H20:
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13
Q

Give some examples of a charged ligand.

A
  • Hydroxide :OH-
  • Cyanide :CN-
  • Chloride :Cl-
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14
Q

Explain what a MONODENTATE ligand is and give an example.

A
  • A ligand which forms 1 coordinate (dative covalent) bond to a central metal ion in a complex ion.
  • NH3, H2O, OH-, CN-, Cl-.
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15
Q

Explain what a BIDENTATE ligand is and give an example.

A
  • A ligand which forms 2 coordinate (dative covalent) bonds to a central metal ion in a complex ion.
  • (en) NH2CH2CH2NH2.
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16
Q

Explain what a HEXADENTATE ligand is and give an example.

A
  • A ligand which forms 6 coordinate (dative covalent) bonds to a central metal ion in a complex ion.
  • (edta4-).
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17
Q

What is the colour of Cu2+(aq)?

A

Blue Solution.

18
Q

What colour is the precipitate formed by adding NaOH dropwise to Cu2+(aq)? What is the ionic equation for the formation of this?

A
  • Blue Precipitate.
  • Cu2+(aq) + 2OH-(aq) → Cu(OH)2(s).
19
Q

What is the colour of Fe2+(aq)?

A

Pale Green Solution.

20
Q

What colour is the precipitate formed by adding NaOH dropwise to Fe2+(aq)? What is the ionic equation for the formation of this?

A
  • Dark Green Precipitate which goes brown standing in air.
  • Fe2+(aq) + 2OH- → Fe(OH)2(s).
21
Q

What is the colour of Fe3+(aq)?

A

Pale Yellow Solution.

22
Q

What colour is the precipitate formed by adding NaOH dropwise to Fe3+(aq)? What is the ionic equation for the formation of this?

A
  • Orange-brown Precipitate.
  • Fe3+(aq) + OH-(aq) → Fe(OH)3(s).
23
Q

What is the colour of Mn2+(aq)?

A

Pale Pink Solution.

24
Q

What colour is the precipitate formed by adding NaOH dropwise to Mn2+(aq)? What is the ionic equation for the formation of this?

A
  • Light brown Precipitate which darkens on standing in air.
  • Mn2+(aq) + OH-(aq) → Mn(OH)2(s).
25
Q

What is the colour of Cr3+(aq)?

A

Violet Solution.

26
Q

What colour is the precipitate formed by adding NaOH dropwise to Cr3+(aq)? What is the ionic equation for the formation of this?

A
  • Grey-green precipitate.
  • Cr3+(aq) + OH-(aq) → Cr(OH)3(s).
27
Q

What colour is the precipitate formed by adding NaOH in excess to Cr3+(aq)? What is the complex ion which is formed?

A
  • The precipitate dissolves and a Dark Green Solution is formed.
  • [Cr(OH)6]3-(aq).
28
Q

What colour is the precipitate formed by adding NH3 dropwise to Cu2+(aq)? What is the ionic equation for the formation of this?

A
  • Blue Precipitate.
  • Cu2+(aq) + 2OH-(aq) → Cu(OH)2(s).
29
Q

What colour is the solution formed by adding NH3 in excess to Cu2+(aq)? What is the equation for the formation of this?

A
  • The precipitate dissolves and a Dark Blue Solution is formed (LIGAND EXCHANGE).
  • [Cu(H2O)6]2+(aq) + 4NH3(aq) —> [Cu(NH3)4(H2O)2]2+(aq) + 4H2O(l).
30
Q

What colour is the precipitate formed by adding NH3 dropwise to Cr3+(aq)? What is the ionic equation for the formation of this?

A
  • Grey-green precipitate.
  • Cr3+(aq) + 3OH-(aq) → Cr(OH)3(s).
31
Q

What colour is the solution formed by adding NH3 in excess to Cr3+(aq)? What is the equation for the formation of this?

A
  • The precipitate dissolves and a Purple Solution is formed (LIGAND EXCHANGE).
  • [Cr(H2O)6]3+(aq) + 6NH3(aq) —> [Cr(NH3)6]3+(aq) + 6H2O(l).
32
Q

What colour change do you see when Cl-(aq) ions are added to Cu2+(aq)? What is the equation of the reaction that takes place?

A
  • Blue Solution to Yellow Solution.
  • [Cu(H2O)6]2+ + 4Cl- ⇌ [CuCl4]2- + 6H2O.
33
Q

What two shapes and bond angles could a 4-coordinate complex have?

A
  • Tetrahedral (109.5°).
  • Square Planar (90°).
34
Q

When filling or removing electrons in an atom, is 4s or 3d filled/ removed first?

A

4s.

35
Q

What shape and bond angle does a 2-coordinate complex have?

A

Linear (180°).

36
Q

What shape and bond angle does a 6-coordinate complex have?

A

Octahedral (90°).

37
Q

Identify 1 transition metal used as a heterogeneous catalyst.

A

Iron (Fe) in the Haber Process or Nickel (Ni) in the hydrogenation of alkenes.

38
Q

What is cis-platin and how does it work? Give it’s formula.

A
  • Cis-platin is a chemotherapy drug which binds to the DNA of cancer cells preventing cancer cell division.
  • [Pt(NH3)2(Cl)2].
39
Q

What type of isomerism can you get with octahedral complexes with 2 or more bidentate ligands?

A

Optical Isomerism.

40
Q

Explain what happens to Haemoglobin in the lungs and close to respiring cells.

A
  • Lungs: Oxygen (O2) binds to Haemoglobin to make Oxyhaemoglobin when oxygens concentration is high.
  • Respiring Cells: O2 ligand of Oxyhaemoglobin is substituted by CO2 to make Carboxyhaemoglobin.