Transition Elements Flashcards

1
Q

What is different about chromium and copper?

A

They fill d orbitals before s orbitals

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2
Q

Why can transition metals form ions with different oxidation states?

A

Easy to lose 4s electrons and 3d electrons as the difference in energy is very small between the 4s and 3d orbitals.

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3
Q

What oxidation state is most common at the start of the d block?

A

+3

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4
Q

What oxidation state is most common at the end of the d block?

A

+2

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5
Q

How can transition elements act as a homogeneous catalyst?

A

Variable oxidation states - Solution of metal can act as a catalyst in aqueous reactions.

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6
Q

How can transition elements act as a heterogeneous catalyst?

A

Empty/available d orbitals at the correct energy level to accept electrons.

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7
Q

What is the catalyst in the contact process?

A

V

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8
Q

What is the catalyst in the Haber process?

A

Finely divided Fe

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9
Q

What is the catalyst in the hydrogenation of alkenes?

A

Use Ni/Pt catalyst

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10
Q

What is the catalyst in the decomposition of Hydrogen peroxide?

A

Co

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11
Q

What is the definition of transition elements?

A

A d block element that forms at least one ion with an incomplete d sub-shell.

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12
Q

What are the chemical properties of transition elements?

A

Form compounds with variable oxidation states
Form coloured compounds
Both elements and their compounds are good catalysts

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13
Q

What are the physical properties of transition elements?

A
Dense
Durable
Ductile
Malleable
High boiling points
High tensile strength
High melting points
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14
Q

Where are lower oxidation states normally found?

A

Simple ionic compounds

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15
Q

Where are higher oxidation states normally found?

A

Molecular ions

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16
Q

When are d block elements coloured in aqueous solution?

A

When they have a partially filled d orbital.

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17
Q

What is the definition of a complex ion?

A

A transition metal ion bonded to one or more ligands by coordinate bonds.

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18
Q

What is the definition of a ligand?

A

A molecule or ion that can donate a pair of electrons to the transition metal ion to form a coordinate bond

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19
Q

What are examples of neutral monodentate ligands?

A

Water

Ammonia

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20
Q

What are examples of charged monodentate ligands?

A

Hydroxide
Thiocyanate
Cyanide
Chloride

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21
Q

What are monodentate ligands?

A

Ligands with one lone pair

22
Q

What are bidentate ligands?

A

Can donate 2 pairs of electrons to the central metal ion to form 2 coordinate bonds.

23
Q

What donates the lone pairs in Ethane - 1,2 - diamine

A

There are 2 N’s with lone pairs that they use to make 2 coordinate bonds.

24
Q

What is the example of a multidentate ligand?

A

EDTA

25
Q

What does the coordination number tell you?

A

How many coordinate bonds a transition metal can form

26
Q

What isomers can be formed by complex ions?

A

Cis - trans

Optical isomers

27
Q

What colour is copper 2+ (aq)?

A

Blue

28
Q

What happens to copper 2+ when NaOH is added?

A

Blue precipitate is formed

29
Q

What colour is Iron 2+ (aq)?

A

Green

30
Q

What happens to Iron 2+ when NaOH is added?

A

Green precipitate is formed

31
Q

What colour is Iron 3+ (aq)?

A

Purple

32
Q

What happens to Iron 3+ when NaOH is added?

A

Brown precipitate is formed

33
Q

What colour is Manganese 2+(aq)?

A

Pink

34
Q

What happens to manganese 2+ when NaOH is added?

A

Brown precipitate formed

35
Q

What colour is chromium 3+ (aq)?

A

Violet

36
Q

What happens to chromium 3+ when NaOH is added?

A

Green precipitate formed

37
Q

What happens to the green precipitate when excess NaOH is added to chromium 3+?

A

Precipitate dissolves

38
Q

What are the equations for reactions of transition metal ions with sodium hydroxide?

A

Mⁿ⁺(aq) + nOH⁻ (aq) -> M(OH)n (s)

39
Q

What is the stability constant K stab?

A

The equilibrium constant for an equilibrium existing between a transition metal ion surrounded by water ligands and the complex formed when the same ion has undergone a substitution reaction.

40
Q

What are the units of Kstab?

A

mol⁻ⁿdm^x

41
Q

What is the equation for the Kstab?

A

[product complex ion] / [reactant complex ion] X [Other reactant ligand]

42
Q

What happens as the value of Kstab gets larger?

A

The position of equilibrium lies further to the right.

The more stable the complex ion.

43
Q

What happens to copper 2+ when NH3 is added?

A

Blue precipitate

44
Q

What happens to Iron 2+ when NH3 is added?

A

Green precipitate

45
Q

What happens to Iron 3+ when NH3 is added?

A

Brown precipitate

46
Q

What happens to Manganese 2+ when NH3 is added?

A

Brown precipitate

47
Q

What happens to Chromium 3+ when NH3 is added?

A

Green precipitate

48
Q

What happens to Copper 2+ when excess NH3 is added?

A

Darker blue solution

Precipitate dissolves

49
Q

What happens to Iron 2+ when excess NH3 is added?

A

Precipitate doesn’t dissolve

50
Q

What happens to Iron 3+ when excess NH3 is added?

A

Precipitate doesn’t dissolve

51
Q

What happens to Manganese 2+ when excess NH3 is added?

A

Precipitate doesn’t dissolve

52
Q

What happens to Chromium 3+ when excess NH3 is added?

A

Purple solution

Precipitate dissolves