Transition Metals

Question 1

Describe what a d-block transition metal is

Answer 1

The d-block transition metals are metals with an incomplete d subshell in at least one of their ions.

Question 2

Describe the anomalies in the Transition metals which do not abide by aufbau

Answer 2

The filling of the d orbitals follows the aufbau principle, with the exception of chromium and copper atoms.

Question 3

Describe why these anomalies copper and cobalt can exist

Answer 3

These exceptions are due to the special stability associated with the d subshell being half-filled or completely filled

Question 4

From the first row of the transition metals, their ions describe the electrons lost in order of subshells eg 4s and 3d

Answer 4

When atoms from the first row of the transition elements form ions, it is the 4s electrons that are lost first rather than the 3d electrons.

Question 5

When is an element said to be in particular oxidation state

Answer 5

An element is said to be in a particular oxidation state when it has a specific oxidation number.

Question 6

How can the oxidation state be determined for
-uncombined elements
-ions containing single atoms

Answer 6

The oxidation number can be determined by the following:
 uncombined elements have an oxidation number of 0
 ions containing single atoms have an oxidation number that is the same as the charge on the ion
 in most of its compounds, oxygen has an oxidation number of −2
 in most of its compounds, hydrogen has an oxidation number of
+1
 the sum of all the oxidation numbers of all the atoms in a neutral
compound must add up to zero
 the sum of all the oxidation numbers of all the atoms in a polyatomic ion must be equal to the charge on the ion

Question 7

A transition metal can have different…

Answer 7

A transition metal can have different oxidation states in its compounds.

Question 8

Describe what could be different about compounds of the same transition meta in different oxidation states

Answer 8

Compounds of the same transition metal in different oxidation states may have different colours.

Question 9

Describe the definition of oxidation and reduction in terms of oxidation states

Answer 9

Oxidation can be defined as an increase in oxidation number. Reduction can be considered as a decrease in oxidation number

Question 10

Describe how oxidation or reduction can be identified in transition metal ions

Answer 10

Changes in oxidation number of transition metal ions can be used to determine whether oxidation or reduction has occurred.

Question 11

Describe how oxidation states determines the type of agent a compound can be

Answer 11

Compounds containing metals in high oxidation states are often oxidising agents, whereas compounds with metals in low oxidation states are often reducing agents.

Question 12

Describe what a ligand is and how they bond to a central atom or ion

Answer 12

Ligands 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 13

Describe the classes of ligands

Answer 13

Ligands can be classified as monodentate, bidentate, up to hexadentate.

Ligands:
Mono-dentate:neutral H2O, NH3,CO. CHARGED- OH,F,CL,BR,I,CN
BIDENTATE-H2NCH2CH2NH2

Question 14

What is the coordination number

Answer 14

The total number of bonds from the ligands to the central transition metal is known as the coordination number.

Question 15

How do you name transition metal complexes?

Answer 15

central metals that obey the normal IUPAC rules
 copper (cuprate) and iron (ferrate)(for negative complex ions)
 ligands, including water, ammonia, halogens, cyanide, hydroxide, and oxalate for
-Metal name ends in ate if it is negative complex
-water becomes OH2 instead and is called aqua, ammonia to ammine.
# if the transition metal doesn’t end in ate it is either positive or neutral
#the O.S of the TM and ligands will add together to give the overall charge

Question 16

What happens to the d orbitals in a complex of a transition metal

Answer 16

In a complex of a transition metal, the d orbitals are no longer degenerate

Question 17

What causes the splitting of d orbitals and the affect this has on the energy on d orbitals

Answer 17

Splitting of d orbitals to higher and lower energies occurs when the electrons present in approaching ligands cause the electrons in the orbitals lying along the axes to be repelled.

Question 18

Describe what strong field ligands and weak field ligands are

Answer 18

Ligands that cause a large difference in energy between subsets of d orbitals are strong field ligands. Weak field ligands cause a small energy difference.

Question 19

The order of ability to split d orbitals is called… series

Answer 19

Ligands can be placed in an order of their ability to split d orbitals. This is called the spectrochemical series.

Question 20

How can the colours of transition metals be explained

Answer 20

Colours of many transition metal complexes can be explained in terms of d-d transitions.

Question 21

What happens when light is absorbed and electrons in a lower energy d orbital take that light in

Answer 21

Light is absorbed when electrons in a lower energy d orbital are promoted to a d orbital of higher energy.

Question 22

Describe how a complementary colour is observed

Answer 22

If light of one colour is absorbed, then the complementary colour will be observed.

Question 23

Describe how the electromagnetic spectrum is observed

Answer 23

Electrons transition to higher energy levels when energy corresponding to the ultraviolet or visible regions of the electromagnetic spectrum is absorbed.

Question 24

What can transition metals and their compounds act as?

Answer 24

Transition metals and their compounds can act as catalysts.

Question 25

Describe a heterogeneous catalyst

Answer 25

Heterogeneous catalysts are in a different state to the reactants.

Question 26

Describe a heterogeneous catalyst

Answer 26

Heterogeneous catalysis can be explained in terms of the formation of activated complexes and the adsorption of reactive molecules onto active sites. The presence of unpaired d electrons or unfilled d orbitals is thought to allow activated complexes to form. This can provide reaction pathways with lower activation energies compared to the uncatalysed reaction.

Question 27

Describe a homogeneous catalyst

Answer 27

Homogeneous catalysts are in the same state as the reactants.

Question 28

Describe homogeneous catalysis

Answer 28

Homogeneous catalysis can be explained in terms of changing oxidation states with the formation of intermediate complexes.