U1: Topic 4 Transition metals

Question 1

What are d-block transition metals?

Answer 1

Metals with an incomplete d sub shell in at least one of their ions.

Question 2

Why do chromium and copper not follow Aufbau principle?

Answer 2

1/2 filled and completely filled sub shells are very stable and so are preferred energetically.

Question 3

Uncombined elements have what oxidation state?

Answer 3

0

Question 4

Ions containing single atoms have an oxidation state that is the same as?

Answer 4

Charge on the ion.

Question 5

Sum of all oxidation states of all atoms in a molecule or neutral ion must add up to?

Answer 5

0

Question 6

The sum of all oxidation numbers of all the atoms in a polyatomic ion must be equal to?

Answer 6

Overall charge on ion.

Question 7

How is it easy for the 3d electrons to be lost when changing oxidation state?

Answer 7

Because 3d energy levels are close to that of the 4s so 3d electrons lost easy to form other oxidation states.

Question 8

Oxidation states can be used to determine what?

Answer 8

Whether oxidation or reduction has happened.

Question 9

An increase in oxidation state shows what?

Answer 9

Oxidation has occurred.

Question 10

A decrease in oxidation state shows what?

Answer 10

Reduction has occurred.

Question 11

It is usually true that high oxidation state compounds tend to be …. and low oxidation state compounds are….?

Answer 11

Oxidising agents
Reducing agents

Question 12

What is a complex?

Answer 12

Metal ion surrounded by ligands.

Question 13

A ligand is an electron ….?

Answer 13

Donor

Question 14

Ligands are negative ions or molecules with what?

Answer 14

Non-binding pairs of electrons that they can donate to the central metal ion.

Question 15

What type of bond do ligands form with the metal?

Answer 15

Dative covalent bonds.

Question 16

Examples of common ligands.

Answer 16

Water
cyanide ions
ammonia
hydroxide ions
halide ions
oxalate ions

Question 17

Ligands are classified according to how many pairs of electrons they donate examples…

Answer 17

Monodentate : one pair of
Bidentate : two pairs
Tridentate : three pairs

Question 18

What is the coordination number?

Answer 18

Total number of bonds from ligands to central transition metal.

Question 19

What is EDTA?

Answer 19

Common ligand used in complexometric titrations to determine quantities of metal ions in a substance. Complexes with metal ions in a 1:1 ratio.

Question 20

In what order should complexes be named?

Answer 20

Ligand (alphabetical)
prefix placed infront (di, tetra)
metal named (negative charge add ate to end)
roman numerals

Question 21

Transition metal complexes are named according to what rules?

Answer 21

IUPAC

Question 22

In a complex of transition metals the d orbitals are no longer what ?

Answer 22

Degenerate

Question 23

What causes the splitting of d orbitals to higher or lower energies?

Answer 23

Electrons present in approaching ligands cause electrons in the orbitals lying along the axes to be repelled.

Question 24

Ligands that cause a large difference in energy between subsets of d orbitals are ….?

Answer 24

Strong field ligands.

Question 25

Weak field ligands cause what?

Answer 25

Small energy difference.

Question 26

What is the spectrochemical series?

Answer 26

Ligands placed in order of their ability to split d orbitals.

Question 27

What is the spectrochemical series?

Answer 27

Ligands placed in order of their ability to split d orbitals.

Question 28

Colours of many transition metal complexes can be explained by?

Answer 28

d-d transitions

Question 29

When is light absorbed?

Answer 29

When electrons in a lower energy d orbital are promoted to a d orbital of a higher energy.

Question 30

If light of one colour is absorbed then what colour with be observed?

Answer 30

The complementary colour.

Question 31

When do electrons transition to higher energy levels?

Answer 31

When energy corresponding to the uv or visible regions of the electromagnetic spectrum is absorbed.

Question 32

Transition metals and their compounds can act as what?

Answer 32

Catalysts

Question 33

Heterogeneous catalysts are in a …..?

Answer 33

Different state to reactants.

Question 34

Heterogeneous catalysts can be explained in terms of?

Answer 34

Formation of activated complexes and adsorption of reactive molecules onto active sites. The presence of unpaired d electrons or unfilled d orbitals allows activated complex to form Provides reaction pathways with lower activation energies compared to uncatalysed reaction.

Question 35

Homogeneous catalysts are in the ….?

Answer 35

Same state as reactants.

Question 36

Homogeneous catalysis can be explained in terms of?

Answer 36

Changing oxidation states with the formation of intermediate complexes.