KA4- Transition Metals

Question 1

What are transition metals

definition

Answer 1

A substance found in the d-block which has at least one ion with an incomplete d-subshell

Question 2

What are metals but are excluded because of the definition used at AH?

Answer 2

Sc (scandium) and Zn (zinc) as Sc has no d subshell and Zn has a full subshell

Question 3

What are the characteristics of transition metals?

Answer 3

• produce ions with different valencies
• produce a coloured compound
• act as a catalyst

Question 4

When converting transiton metal atoms into their ions (drawing the box orbital notation) what is the rule to use?

Answer 4

always remove 4s electrons before the 3d electrons

Question 5

oxidation states

Answer 5

transition metals exibit different oxidation states of varying ability because they cannot only use their 4s electrons but some or all of their 3d electrons

Question 6

oxidation number

Answer 6

how many electrons have been lost

Question 7

What are the rules for oxidation states?

Answer 7

1. simple ions (na+, K+, Cl-) count as +1 or -1
2. oxygen is always assumed to be -2
3. hydrogen is lways assumed to be +1
4. overall charge on a compound is always 0 (but the overall charge for ions)
5. in polyatomic ions, the sum of all the oxidation numbers is eual to the overll charge on the ion

Question 8

What is monodentate ligands?

give an example

Answer 8

• only form one daitive bond
• H2O, NH3, Cl-, CN-, OH-

Question 9

What is a ligand?

Answer 9

Molecule or anion (more electron than proteins) which attach to the meta atom in a complex via diative covalent bonds

Question 10

What is a bidentate ligand?

give an example

Answer 10

• can form 2 daitive bonds
• oxalato

Question 10

What is a polydentate ligand?

Answer 10

• multiple donor sites
• EDTA, chlorophyll, Haemaglobin

Question 10

Name the 5 rules for naming coordination compoounds?

Answer 10

1. cation pecides naming anion
2. complex ion names are one word

Question 10

What are the rules concerning forming a complex?

Answer 10

• The cation or anion cannot exit on their own and must have their charge balanced
• the complex ion wil bond with oppositely charged ions to form a ccomplex
• cation is +ve
• anion is -ve

Question 10

What is responsible for the characteristic colours seen in so many transition metal compounds?

Answer 10

the ligands surrounding the metal ions

Question 11

How are the circumstances created that lead to the adsorption of some light from the visible spectrum?

Answer 11

interactions between the ligands and electrons

Question 12

What does the binding of ligands to metal ions cause?

Answer 12

d->d transitions
causes orbitals to split (when ligands are involved)

Question 13

Why are transition metals good exxamples of catalysts?

Answer 13

• due to the existence of partially filled d-orbitals with unpaired electrons
• ability to change oxidation states so easily

Question 14

Heterogeneous & Homogeneous

definitions

Answer 14

1. different state to reactants
2. same state to reactants

Question 15

How are there alternative reaction pathways with tranisiton metals acting as the catalysts that provide lower activation energy?

Answer 15

the presence of unpaired d-electrons or empty d-orbitals allow intermediate complexes to form

Question 16

What is the coordination number?

Answer 16

How many bonds the metal makes

Question 17

When asked the classification of a ligand, what does this mean?

Answer 17

How many bonds a ligand is making

Question 18

If white light was shone on a copper colbalt complex what would it adsorb and then give off?

Answer 18

It would adsorb yellow light so therefore give off blue light

Question 19

Why do d-orbitals split?

Answer 19

When a ligand comes into contact with a transition metal the d-orbitals split as the electrons are replused wanting to go to the next possible energy level (this is created by the splitting of the d-orbitals

Question 20

How to transition metals absorb light?

Answer 20

lower energy d orbitals can absorb energy anf move to higher energy d orbitals

Question 21

Concerning the colours we see in transition metals, why do we see these colours?

Answer 21

• where the ligand is on the spectrochemical series
• we will see the white light minus the colour adsorbed