Transition metals

Definition of transition metals

Can form IONS with incomplete d orbital

properties of transtion metals

Act as catalyst

Form complexes

Form coloured compounds

Variable oxidation states

Explain why transition metals form variable oxidative staes and hence coloured ions

The energy levels of adjacent s orbital and d orbital are close in energy so multiple electrons can be removed from d orbital

severel ions can be formed whilst still being stable

Whats the bonds are always present in complex ions

Dative bond between lone pair on ligand and metal ions

Definition of complex ion

Metal ion surrounded by coordinately bonded ligand

Define ligand

Ion/molecule which donates lone pair of electron to metal ion

Types of ligands and define them

Monodentate- donates 1 lone pair to central metal ion forming 1 coordiante bond

Bidentate-each donates 2 lone pairs to central metal ion to form coordination bonds of 2

Multidentate- each donates multiple lone pairs of electrons to form more than 2 coordianation bonds

Define Co ordination number

Number of coordinate bomds to the central metal ion

Example of monodentates

NH3

H2O

Cl-

Why cant electron pair repulsion theory be used to predict shape of complex ions

too many electrons in d orbital

Factors affecting shape of complex metal ion

Size of ligand

Coordination number

What ligands do octahedral complexes generally have and why?

NH3/H2O

smalll molecules so can fit around central metal ion easily

Properties of octahedral complexes

Coordination number of 6

Bond angle: 90

Can tetrahedral complexes contain Cl-

Yes they can , as Cl- is lare so only 4 can fit

Tetrahedral complex properties

Coordination number of 4

Bond angle - 109.5

What are the only 2 metals that can form square planar complexes

Pt2+ and Ni2+

What metal forms linear complex

Ag+

What must you have in an octahedral conplex to have cis-trans isomerism

4 of 1 monodentate and 2 of a different monodentate

What type of isomerism do tetrahedral structures display

None

What type of isomerism do square planar show

cis-trans

What type of isormerism do octahedral complexes show ?

Optical and cis-trans

Formula for Cisplatin and shape of the complex and bond angle

Pt(NH3)2Cl2

square planar

90 degrees

What processs does cisplatin prevent and how

DNA replication by ligand substitution reaction betweeen guanine base and Cl -

Why and what are there risks associated with cisplatin

Why?

prevents healthy blood cells from repruding such as :

Blood cells

Hair cells

By attatching to DNA in normal healthy cells

What?

Supresses immune system leading to increased risk of infection

Hair loss

Kidney damage

How can side effects of cisplatin be minimised

Use small amounts

Target the application to tumour

What are the 3 types of catalyst and define them

Heterogeneous-Catalyst and reactant are in different physical states

Homogeneous-catalyst and reactant are in same physical state

Autocatalyst-cataylst is in same physical state as reactants but the catalyst is a reaction product

Examples of reactions including heterogenous catalyst and which ones

1)Contact process

SO2 + ½ O2 turns to SO3

Catalyst: V2O5

2)Harber process

N2+3H2 turns to 2NH3

Catalyst: Fe

3)Methanol production

Co + 2H2 forms methanol

Catalyst: Chromium(III) oxide

Contact process equation

1) SO2 + V2O5 forms SO3 + V2O4-

2) V2O4 + ½ O2 forms V2O5

IN the contact process why is small pellets of V2O5 used?

Increases surface area

Mechanism of action for heterogeneous catalyst

1) Reactants are adsorbed on active site on surface of catalyst

2) Bonds in reactants weaken and break and new bonds are formed by a reaction on catalyst surface

3) products are desorbed

Benefits of adsorption

1)Weakens bond within reactant molecules making it easier to break, therefore lowering activation energy

2)Increases surface concentration of reactant molecules therefore increases collision frequncy and rate of reaction

3)Provide reactants with correct orientation for reaction to occur