TRANSITION METAL CHEM

Question 1

to oxidise a tm to a higher oxidation state what must you add

Answer 1

an alkali followed by an oxidising agent

Question 2

how woukd you stabilise a tm with a low oxidation state such as fe2+

Answer 2

place in acidic conditions

Question 3

define a tm

Answer 3

a partially filled d orbital

Question 4

what are some chemical properties of a tm

Answer 4

variable oxidation states
partially filled d orbitals
form colourful compounds
can form complex ions
they are good catalysts

Question 5

what is a ligand

Answer 5

will donate a pair of electrons around the central metal ion to form coordinate bonds

Question 6

what is a monodentate ligand

Answer 6

has only one coordinate bond around the central metal ion

Question 7

what is the coordination number of a complex ion

Answer 7

how many coordinate bonds the ion has

Question 8

can a bidentate ligand form optical isomers

Answer 8

yes

Question 9

define a bidentate ligand

Answer 9

donates two electron pairs to a tm from different atoms on the same molecule

Question 10

define entropy

Answer 10

amount of disorder in a system

Question 11

what happens when you add EDTA to a solution of TM salts

Answer 11

the EDTA will replace all six water ligands in the hexa-aqua ion

Question 12

how can a more stable complex form

Answer 12

increase entropy

Question 13

describe what a cis molecule looks like

Answer 13

same side

Question 14

describe what a trans molecule looks like

Answer 14

across from one another

Question 15

which is larger ammonium ion or chloride ion

Answer 15

chloride - this will affect shape - and effect hoe many ions can fit around the central metal ion

Question 16

are scandium and zinc tms

Answer 16

no - because they do not have partially filled d orbitals - they are full when they form stable ions
sc3+ has the configuration as Ar
Zn2+ - Ar 3d10 4s2

Question 17

what are some physical properties of a tm

Answer 17

high density
high melting and boiling points

Question 18

what type of isomerism is optical isomerism

Answer 18

stereoisomerism

Question 19

define stereoisomerism

Answer 19

same molecular formula but different orientation of their bonds in space

Question 20

how does colour arise in a tm

Answer 20

electronic transition from the ground state to the excited state. visible light is absorbed to promote these d-electrons to go to higher states. the light that is not absorbed is transmitted through a solution or reflected in a solid to give colour

Question 21

what is the equation for the speed of light

Answer 21

speed of light = wavelength x frequency
c=lamda x f

Question 22

what does the frequency of light absorbed depend upon

Answer 22

the energy difference between levels

Question 23

what effects energy in an ion complex

Answer 23

the oxidation state of the central metal ion
ligands - shape -
- coordination number

Question 24

do ligands intensify colour

Answer 24

yes

Question 25

how do you dimerise a complex

Answer 25

add acid

Question 26

how do you monomerise a complex

Answer 26

add an alkali

Question 27

when oxidising low oxidation states why is an alkali added

Answer 27

there is a greater tendency to form negative ions
OH-

Question 28

explain the steps of colourimetry

Answer 28

make a metal ion solution of known concentrations
of decreasing concentrations - dilution series
- measure the percentage absorption in the colourimeter
- measure the unknown concentration’s percentage absorption

• plot a calibration curve
• interpolate the graph to find the unknown conc