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Flashcards in Transiton Metals Deck (45)
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1

What are transition metals

They are metals that form at least one stable ion with partially filled d orbitals

2

Why aren't zinc and scandium considered transition metals

Scandium only forms 3+ions with no electrons in the d orbital

Zinc only forms 2+ ions with a full d block

So they don't form partially field d blocks

3

What are 4 properties of transition metals

Complex ion formation
Formation of coloured ions
Variable oxidation state
Catalytic activity

4

What is a ligand

It's a molecule that forms a co ordinate bond with a transition metal by donating pair of electrons

5

What is a complex ion

It's a central metal atom surrounded by ligands and forms dative covalent bonds

6

What is the co ordination number

The number of co ordinate bonds to the central metal ion

7

State the ligands that form 6 bonds around a metal ion

NH3
H2O

8

State the ligands that form 4 bonds

CL
CN

9

What is a monodente ligand

One that has only one atom with a lone pair of electrons which forms bonds with a transition metal ion

10

What is a multidentate ligand

When it has more than one atom with a lone pair of electrons and it forms bonds with transition metal ions

11

What is the chelate effect and why does it occur

That bi dentate and multidente ligands replace monodentate ligands from complexd as they increase entropy for the reaction

There are moles of products than reactants from2-7 this creates more disorder

12

Give an example of bidente ligands

En
C2O4(2-)

13

What are the 4 shapes that complex ions form and give examples

Octahedral
Square planer-cisplatin (Pt)(NH3)2 (CL)2

Tetrahedral-[CO(CL)4

Linear- NH3--Ag--NH3

14

State how many coordinate bonds CN,H20,OH,NH3

6

15

How many co ordinate bonds does CL

4

16

State the types of isomerism that complex ions form

Optical isomerism
Cis-trans isomerism

17

State what optical isomerism and how it's shown in complex ions and how can they be distinguished

Two non imposable mirror images are formed they can be distinguished by passing plane polarised light through the mixture and the enantiomers rotate them in equal but opposite directions

18

State the use of AG(NH3)

It's used as tollens reagent

19

Give the use of cisplatin and how it works

It's an anti cancer drug it prevents the cancer cell from replicating

20

What 3 factors affect colour changes in transition metals

Ligand
Co-ordination number
Oxidation state

21

Why does s change in ligand or coordination number result in a change in colour

It alters the energy split between the d-orbitals which changes the energy difference so the frequency of light absorbed changes

22

Why do transition metals have different colours

When light hits a transition metal it's absorbed which causes electrons to rise to from ground state to an excited state

The light that isn't absorbed is transmitted which give the substance colour

23

Why do Sn and Zn not have colour

SN ion doesn't have any d electrons left

While Zn and cu have full n d blocks do there's no energy transfer

24

In redox titration state what acid is used and why HCL and nitric acid can't be used

Conc HCL can't be used as the CL- ions will be oxidised to chlorine

Nitric acid can't be used as it's an oxidising agent which leads to a small volume of managanate being produced

So dilute H2SO4 is produced

25

What is the difference between heterogenous catalyst and homogenous catalyst

Heterogenous is in a different phase than the reactants

Homogenous is in the same phase as reactants

26

Give a way to improve the effectiveness of a catalyst

Increase the surface area

27

Give an example of a homogenous catalyst and state where it's used

Fe 2+

Reaction between I- and S2O8 2-

28

Give the equation for the catalyses reaction between I- and S2O82-

S2O8(2-) +2Fe(2+) -> 2SO4(2-) +2Fe3+

Stage 2- 2I- +2Fe(3+) ->2Fe2+ +I2

29

Why is the Uncatalysed reaction between iodide and persulphate ions slow

Because the reaction needs the collision between two negative ions and they repel meaning high activation energy

30

Why do the individual stages in the catalysed mechanism result in lower activation energies

As it involves collision between positive and negative lonw