Transition metals

Question 1

Formal definition of transition metal

Answer 1

Forms stable ion with partially filled d shell

Question 2

For e arrangement, what classifies a transition element

Answer 2

Partially filled / incomplete d sub shell/orbiatal

Question 3

Which d block elects are not trans metals

Answer 3

Sc, only forms Sc3+,
3d0
Zn, only forms Zn2+,
3d10

Question 4

Chemical properties of trans metals

Answer 4

Variable oxi states
Forms coloured ions
Catalytic
Forms complex ions

Question 5

Define complex ion

Answer 5

Central metal ion surrounded by coordinately bonded ligands
Ions coordination number exceeds oxidation state

Question 6

Define ligand

Answer 6

Atom/Ion/Molecule that can donate lone electron pair

Question 8

Example of monodente ligands

Answer 8

H20, NH3, Cl-

Question 9

Aqua ions

Answer 9

Dissolved the salt of an trans metal in water
6 water molecules surround metal ion

Question 10

Difference between mono bi and multi dente (for understanding)

Answer 10

Mono - binds though one donor atom, forms one coordinate bond
Bi - one molecule bonds through two donor atoms, forms two coordinate bonds
Multi - binds through more than two donar atoms

Question 11

Example of multidente ligand

Answer 11

EDTA4-
Replaces all 6 ligands

Question 12

What’s chelate

Answer 12

Complex ions with polydente ligands

Question 13

What’s the chelate effect

Answer 13

When a multi/bidente replaces a monodente
Number of particles increase
Entropy increases

Question 14

Size of monodente ligands and significance

Answer 14

NH3 & H2O similar size
When ligands exchange no change on coordination number
Cl- ligand is bigger so when exchanged by NH3 or H2O coordination number changes

Question 15

What’s haem

Answer 15

Fe (II) complex with multidente ligand

Question 16

How does haemoglobin transport oxygen

Answer 16

O2 forms coordinate bond to Fe(II) in haemoglobin
Transports O2 in the blood

Question 17

Why is CO toxic

Answer 17

It bonds to the iron / haemoglobin
Displaces O2

Question 18

Tetrahedral & square planar

Answer 18

Tetrahedral XCl4

Question 19

What does Ag+ form

Answer 19

Linear complex
[Ag(NH3)2]+

Question 20

Why are trans metals complexes coloured (long explanation)

Answer 20

Partially filled d orbitals make it possible for e to move from one d orbital to another
e move from one d orbitals to another one of a higher energy level (exited state)
They absorb energy
Wavelengths of visible lights absorbed and the remains are transmitted

Question 21

Which colours have high and low f/v

Answer 21

Violent high f & E
Red low f & E

Question 22

What leads to change in E

Answer 22

Change in oxidation state
Change in coordination number
Ligands

Question 23

How is colorimeter used

Answer 23

With a calibration graph
Can measure concentration of solutions of coloured transitions metal compounds

Question 24

How does calorimeter work

Answer 24

Uses light source and detector
Measures amount of light of a particular wl that passes through coloured solution
More concentrated less light transmitted through solution

Question 25

How is a coordinate bond formed

Answer 25

e pair on ligand Donated from ligand to central metal ion

Question 26

How to use calorimetry to determine concentration of complex in water

Answer 26

Make calibration curve by plotting absorbance against concentration for known conc of complex Add excess of ligand to sample of water Find absorbance of sample Use calibration graph to find concentration of complex ion

Question 27

In calorimetry, why should container of each sample have same dimensions

Answer 27

Absorbance depends on distance travelled through solution

Question 28

Why is coloured filter used in calorimetry

Answer 28

Improves accuracy of the value of absorption Filter only allows wl of light that’s absorbed by sample

Question 29

Why might calorimetry be chosen instead of titration

Answer 29

Quicker to analyse Smaller volume of sample can be used