Developing Metals(DM) Flashcards

1
Q

What are complexes?

A

A central metal atom or ion surrounded by a number of negatively charge ions possesing a lone pair of electrons

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2
Q

What are ligands?

A

Molecules or anions which attach themselves to the central TM ion by using a lone pair of electrons

They form a dative covalent bond or coordinate bond

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3
Q

What is meant by a monodentate,bidentate or hexadentate?

A

This signifies the number of covalent bonds formed by a ligand
Monodentate=One covalent bond Bidentate=Two covalent bonds Hexadentate=Six covalent bonds

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4
Q

What are the four rules used to name complex ions?

A
  1. Number of ligands e.g. mono-,di- amd tetra-
  2. Identify the ligands e.g ending -o for anions H2O is aqua and NH3 is amine
  3. Name the central ion e.g copper
  4. Indicate the oxidation state e.g copper (II)
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5
Q

What are the colour of copper(II), iron(II) and iron(III) solutions?

A

Copper(II)=Blue solution
Iron(II)=Green solution
Iron(III)=Brown solution

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6
Q

What is the formula of the precipitate formed when copper(II) reacts with sodium hydroxide and ammonia solution?

Include the co-products

A
  • Sodium hydroxide=Cu(OH)2 (s) and H20
  • Ammonia solution=Cu(OH)2 or Cu(NH3)4
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7
Q

Define coordination number

A

The number of bonds from the central ions to ligands

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8
Q

What are the ligands in hexaquacopper (II) and describe why it was given its name?

A
  • Hex- because it has six ligands
  • -Aqua- because all of its ligands are water
  • Copper because the central ion is a copper ion
  • Copper (II) because the oxidation state of copper is +2
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9
Q

How do you calculate the overall charge of a complex ion?

A

The sum of the charge on the central ion and the charges of the ligands

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10
Q

Describe why not all d-block elements are transition metals

A

Transition metals have a partially full d sub-shell this means at least 3d1 and below 3d10

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11
Q

What is the filling and emptying order of electrons sub shells?

A

Filling=1s 2s 2p 3s 3p 4s 3d
Emptying=4s 3d 3p 3s 2p 2s 1s

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12
Q

What are the five features of a transition metal?

A
  1. Colourful compounds
  2. Used as catalysts
  3. Multiple ions with various oxidation states
  4. Form complexes
  5. Ion of element has partially filished d subshell
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13
Q

Why is zinc not a transition metal?

A

Zinc ion has a full d sub shell

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14
Q

What is hetergeneous and homogeneous catalysis?

A
  • Hetergenous=The catalyst is in a different state to the reactants
  • Homogeneous=The catalyst is in the same state as the reactants
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15
Q

How does heterogenous catalysis involving a TM occur?

A

TM use electrons of atoms on the metal surface to form weak bonds to reactants
Once the reaction is over these bonds are broken

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16
Q

How does homogeneous catalysis involving a TM occur?

A

TM ion forms an intermediate compound with one or more of the reactants
This is then broken down to form the products

17
Q

Why are TM effective catalysts in redox reactions?

A

They can readily move from one oxidation state to another

18
Q

What is formed when Copper(II) reacts with:
* sodium hydroxide
* ammonia solution

A
  • Blue ppt
  • Dark blue solution
19
Q

What is formed when Iron(II) reacts with sodium hydroxide?

Iron(II) is a green solution

A

A dirty/dark green ppt

20
Q

What is formed when iron(III) reacts with sodium hydroxide?

Iron(III) is an orange solution

A

Brown/orange ppt

21
Q

What happens when d block compound absorbs light?

A
  • Light is only absorbed if the energy matches the energy gap between energy levels in atom
  • One electron becomes excited and is promoted to a higher energy level
  • The frequency of light absorbed is dependent on the energy gap
    The colour seens corresponds to the transmitted light which is not absorbed
22
Q

What can affect the colour of a TM?

A
  • Number of d-electrons in TM ion
  • Arrangement of ligands around the ion~affects the splitting of the d sub-shell
  • Nature of the ligands
23
Q

What is ligand substitution?

A

Reactions occur when one ligand displaces another
Ligand substitution occurs if the new complex formed is more stable than the previous complex

24
Q

What happens to the ion with the more positive electrode potential in a redox reaction?

A
  • Donates electrons
  • It is oxidised
  • It is the reducing reagent
25
Q

How do you balance a redox equation?

A
  • Balance oxygen with H2O
  • Balance hydrogen in water with hydrogen ions
  • Balance charges with electrons
26
Q

Why is a salt bridge needed when making a cell from two half-cells?

A

A salt bridge allows the movement of ions

27
Q

How do you work out the potential difference of the cell as a whole?

A

More positive - Least positve

28
Q

How can electorde potentials be used to make predicitons?

A

It allows us to predict whether a reaction is feasible or not

29
Q

What are the two half equations involved in rusting?

A
  • 2e- + 1/2O2 +H2O——->2OH-
  • Fe(s)——>(Fe2+) + 2e-
30
Q

What is the formula of rust?

A

Fe2O3.xH2O

31
Q

Describe sacrififcal protection

A

Protects steel from rust by providing a barrier between the metal and the atmophere
* Zinc layer is protected from corrosion by a firmly adhered layer of zinc oxide

ZInc ocorrodes in preference of iron as iron has a more positive electrode potential~Zinc is oxidised

32
Q

Describe impressed current

A

This involves making the metal the cathode site~Reduction occurs instead of oxidation
* This is done by supplying it with electrons by the application of an emf from an external electrical source
* The metal is now a protected cathode

33
Q

How is the shape of complexes determined?

A
  • Coordination number six=Octahedral
  • Coordination number four=Tetrahedral or Square planar
  • Coordination number two=Linear