chemistry - unit 1.3

Question 1

What are the d-block transition metals?

Answer 1

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

Question 2

What does the filling of the d-orbitals follow?

Answer 2

The aufbau principle, with the exception of chromium and copper atoms.

Question 3

What are these exceptions due to?

Answer 3

The special stability associated with the d subshell being half-filled or completely filled.

Question 4

When atoms from the first row of the transition elements form ions, which electrons are lost first?

Answer 4

The 4s electrons that are lost first rather than the 3d electrons.

Question 5

When is an element said to be in a particular oxidation state?

Answer 5

When it has a specific oxidation number.

Question 6

What do uncombined elements have an oxidation number of?

Answer 6

0

Question 7

What do ions containing single atoms have an oxidation number of?

Answer 7

The same as the charge on the ion.

Question 8

In most of its compounds, what does oxygen have an oxidation number of?

Answer 8

-2

Question 9

In most of its compounds, what does hydrogen have an oxidation number of?

Answer 9

+1

Question 10

What must the sum of all the oxidation numbers of all the atoms in a neutral
compound add up to?

Answer 10

0

Question 11

What must the sum of all the oxidation numbers of all the atoms in a polyatomic ion equal?

Answer 11

The charge on the ion.

Question 12

What can a transition metal have?

Answer 12

Different oxidation states in its compounds.

Question 13

What may compounds of the same transition metal in different oxidation states have?

Answer 13

Different colours.

Question 14

What can oxidation be defined as?

Answer 14

An increase in oxidation number.

Question 15

What can reduction be defined as?

Answer 15

A decrease in oxidation number.

Question 16

What can be used to determine whether oxidation or reduction has occurred.

Answer 16

Changes in oxidation number of transition metal ions.

Question 17

What are compounds containing metals in high oxidation states often?

Answer 17

Oxidising agents, whereas compounds with metals in low oxidation states are often reducing agents.

Question 18

What are ligands?

Answer 18

They may be negative ions or molecules with non-bonding pairs of electrons that they donate to the central metal atom or ion, forming dative covalent bonds.

Question 19

What can ligands be classified as?

Answer 19

Monodentate, bidentate, up to hexadentate.

Question 20

How can you deduce the ligand classification?

Answer 20

From a formula or structure of the ligand or complex.

Question 21

What is known as the coordination number?

Answer 21

The total number of bonds from the ligands to the central transition metal.

Question 22

In a complex of a transition metal, what are the d-orbitals?

Answer 22

No longer degenerate.

Question 23

When does splitting of d-orbitals to higher and lower energies occur?

Answer 23

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

Question 24

What do you call ligands that cause a large different in energy between subsets of d-orbitals?

Answer 24

Strong field ligands.

Question 25

What do weak field ligands cause?

Answer 25

A small energy difference.

Question 26

What is the spectrochemical series?

Answer 26

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

Question 27

What can the colours of many transition metal complexes be explained in terms of?

Answer 27

d-d transitions.

Question 28

When is light absorbed?

Answer 28

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

Question 29

When do electrons transition to higher energy levels?

Answer 29

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

Question 30

What light of one colour is absorbed, what will be observed?

Answer 30

The complementary colour.

Question 31

What can transition metals and their compounds act as?

Answer 31

Catalysts.

Question 32

What are heterogeneous reactants in?

Answer 32

A different state to the reactants.

Question 33

How can heterogeneous catalysis be explained in terms of?

Answer 33

The formation of activated complexes and the adsorption of reactive molecules onto active sites.

Question 34

What is thought to allow activated complexes to form?

Answer 34

The presence of unpaired d-electrons or unfilled d-orbitals.

Question 35

What can heterogenous catalysts provide?

Answer 35

Reaction pathways with lower activation energies compared to the uncatalysed reaction.

Question 36

What are homogeneous catalysts in?

Answer 36

The same state as the reactants.

Question 37

How can homogeneous catalysis be explained in terms of?

Answer 37

Changing oxidation states with the formation of intermediate complexes.