Transition Metals Flashcards

1
Q

Why do the electron arrangements of the transition metals explain their overall similarity?

A

In general there are two outer 4s electrons and as you go across the period, electrons are added to the inner 3d sub-level

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2
Q

Name some properties of the elements from titanium to copper

A
  • good conductors of heat and electricity
  • hard
  • strong
  • shiny
  • have high melting and boiling points
  • fairly low chemical reactivity
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3
Q

How does Copper differ from the general electronic configuration of the transition metals?

A

The d-sub-Level is full (3d10) in Copper and there is only one electron in the 4s outer level

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4
Q

How does Chromium differ from the general electronic configurations of transition metals?

A

It has a half full 3d-sub-level (3d5) and only one electron in the 4s outer level. It is believed that a half full d-level makes the atoms more stable in the same way as a full outer main level makes the noble gas atoms stable

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5
Q

Give the electronic configuration of Copper and a Copper 2+ ion.
(Atomic number is 29)

A

Copper = 1s2 2s2 2p6 3s2 3p6 3d10 4s1

Copper 2+ ion = 1s2 2s2 2p6 3s2 3p6 3d9

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6
Q

Give the electronic configuration of chromium and the chromium 3+ ion
(Atomic number is 24)

A

Chromium = 1s2 2s2 2p6 3s2 3p6 3d5 4s1

Chromium 3+ ion = 1s2 2s2 2p6 3s2 3p6 3d3

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7
Q

Where are electrons lost from when ions are formed in transition metals?

A

Electrons are first lost from the 4s sub-level

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8
Q

What is the formal definition of a transition metal?

A

One that forms at least one stable ion with a part full d-shell of electrons

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9
Q

What are the four main fractures of transition metals that are common to all the elements?

A
  • variable oxidation states: they have more than one oxidation state in their compounds which means they can take part in many redox reactions
  • colour
  • catalysis: catalysts affect the rate of reaction without being used up or chemically changed themselves
  • complex formation: transition elements form complex ions
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10
Q

What bonds do all transition metal ions form?

A

Coordinate/ dative bonds as they accept electron pairs from other ions or molecules

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11
Q

What is a ligand?

A

An ion or molecule with a lone pair of electrons that forms a coordinate bond with a transition metal

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12
Q

What is the coordination number?

A

The number of coordinate bonds to ligands that surround the d-block metal ion

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13
Q

What shape do ions with the coordination number 6 have?

A

Octahedral

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14
Q

What shapes are ions with coordination number 4?

A

Mostly tetrahedral but some complexes are square planar

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15
Q

What shape ions do Ag+ complexes form? And what are the bond angles?

A

Linear and 180 degrees

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16
Q

What shape do Pt2+ and Ni2+ complexes form and what are the bond angles?

A

Square planar and 90 degrees

17
Q

What are the bond angles of tetrahedral complexes?

A

109.5 degrees

18
Q

What happens when you dissolve the salt of a transition metal in water?

A

The positively charged metal ion becomes surrounded by water molecules acting as ligands. Such species are called aqua ions

19
Q

What are multidentate ligands?

A

Molecules or ions with more than one atom with a lone pair of electrons which can bond to a transition metal ion

20
Q

Why is Ethane-1,2-diamine a bidentate ligand?

A

Each nitrogen has a lone pair which can form a coordinate bond to the metal ion. The name of this ion is often abbreviated to ‘en’. It is a neutral ligand

21
Q

What is the charge on an EDTA ion?

A

4-

22
Q

What are chelates?

A

Complex ions with polydentate ligands

23
Q

What can chelates be used for?

A

To remove d-block metal ions from solution

24
Q

What happens when a polydentate ligand is added to a solution of a transition metal ion salt?

A

The chelates will replace all 6 water ligands in the aqua ion

25
Q

Why are chelate complexes favoured over complexes with monodentate ligands?

A

Because the increase in the number of particles causes a significant increase in entropy which drives the reaction to the right- the chelate effect

26
Q

What are isomers?

A

Isomers are compounds with the same molecular formula but with different arrangements of their atoms in space

27
Q

Why can’t chloride ions form octahedral complexes?

A

Because they’re larger ligands than those such as ammonia and so fewer ligands can fit around the central metal ion

28
Q

In which complexes does geometrical isomerism take place?

A

Octahedral and square planar complexes

29
Q

In transition metal complexes, when does optical isomerism occur?

A

When there are two or more bidentate ligands in a complex

30
Q

Why are optical isomers said to be chiral?

A

Because they have an effect on plane-polarised light. One isomer with rotate the plane polarised light in one direction and the other isomer in the opposite direction

31
Q

What causes transition metals to be coloured?

A

The compounds absorbing energy that corresponds to light in the visible region of the spectrum

32
Q

Explain how a solution appears purple in terms of light absorption

A

If a solution appears purple, it is because it absorbs all the light from a beam of white light shone at it except red and blue. The red and blue light passes through and the solution appears purple

33
Q

Why are transition metal complexes coloured?

A

Transition metal compounds are coloured because they have part-filled d-orbitals. It is therefore possible for electrons to move from one d-orbital to another.
In an isolated transition metal atom, all the d-orbitals are of exactly the same energy but in a compound the presence of other atoms makes the d-orbitals have slightly different energies. Therefore, when electrons move between orbitals, they often absorb energy in the visible region of the spectrum. This colour is therefore missing from the spectrum and you see the combination of the colours that aren’t absorbed

34
Q

Give the equation which relates energy difference, frequency and Planck’s constant

A

^E= hv