U2 S4-Transition metals

Question 1

Transition Metals

Answer 1

Metal that can form one or more stable ions with an incomplete d subshell

Question 2

rules of electron configuration

Answer 2

1- e- fill the lowest energy sub-levels first

2-e- fill orbitals before sharing orbitals

Question 3

4s sub-shell fills up before 3d sub shell

Answer 3

4s sub-shell has a lower energy level than 3d sub-shell despite having a higher principal quantum number

Question 4

which 2 elements deviate from the electron configuration rules

Answer 4

Chromium (Ar) 3d5, 4s1 = 1e- in each orbital of 3d sub-level + 1 in 4s sub-level is more stable
Copper (Ar) 3d10, 4s1 = full 3d sub-level + 1e- in 4s sub-level is more stable

Question 5

Physical properties of Transition metals

Answer 5

1-High density

2-High MP and BP

Question 6

Chemical properties of Transition metals

Answer 6

1-form complex ions
2-form coloured ions
3-good catalysts
4-can exist in variable oxidation states

Question 7

Transition metal ions are removed first from

Answer 7

4s e- removed first before 3d e- sub-level

Question 8

Which 2 3d sub-level elements are nor transition metals

Answer 8

Sc (Ar) 4s2,3d1 - (Sc3+) loses 3e- (Ar)

Zn (Ar) 4S2, 3d10 - (Zn2+) loses 2e- (Ar) 3d10

Question 9

Why Sc and Zn not transition metals

Answer 9

Sc forms (Sc3+) - empty 3d sub-level
Zn forms Zn2+ - full 3d sub-level
Zn2+ and Sc3+ are the only stable ions formed
-dont form incomplete sub-levels that cause transition metal chemical properties

Question 10

Why transition metals show variable oxidation states

Answer 10

The energies of the 4s and 3d sub-levels are similar so e- gained or lost using similar amounts of energy

Question 11

chemical properties of transition metals caused by

Answer 11

the incomplete 3d sub-level electron configuration

Question 12

Physical properties of an element determined by

Answer 12

the atomic mass (Ar) of the atom

Question 13

Chemical properties of an element determined by

Answer 13

electron configuration

Question 14

Complex ion

Answer 14

metal surrounded by co-ordinately bonded ligands

Question 15

Co-ordinately bond

Answer 15

covalent bond in which both shared e- pairs are donated from the same atom

Question 16

ligands

Answer 16

atom, ion or molecule that donates a pair of e- to a central positive metal ion

Question 17

monodentate

Answer 17

ligands that can only form one co-ordinate bond with central metal ions

Question 18

Multidentate

Answer 18

ligands that can form more than 2 co-ordinate bonds with central metal ion

Question 19

Bidentate

Answer 19

ligands that can form 2 co-ordinate bonds with central metal ion

Question 20

Oxidation state of central metal ion =

Answer 20

= total charge of complex- sum of charges of the ligands

Question 21

Co-ordination number

Answer 21

Number of co-ordinate bonds between the ligands and central metal ion

Question 22

6 co-ordinately bonded ligands shape

Answer 22

1-octahedral

Question 23

4 co-ordinately bonded ligands shapes

Answer 23

1-tetrahedral

2-square planar

Question 24

2 co-ordinately bonded ligands shapes

Answer 24

1- linear shape

Question 25

Small ligands types and co-ordination number

Answer 25

- H2O + NH3 - 6 co-ordination number - Octahedral

Question 26

large ligands types and co-ordination number

Answer 26

- (Cl-) - 4 co-ordination number - Tetrahedral

Question 27

stereoisomerism

Answer 27

has same structural formula different arrangement of atoms in space

Question 28

Optical isomerism/ Enatiomers

Answer 28

same structural formula but with 4 different groups arranged around a chiral C atom so its a non-superimposable mirror image of the other molecule

Question 29

optical isomerism occurs in

Answer 29

octahedral complexes with 3 Bidentate ligands

Question 30

Cis-Trans isomerism

Answer 30

-Type of E/Z isomerism with 2 groups attached to C atoms around C=C double bonds are the same

Question 31

Cis-Trans isomerism in square planar complex ions

Answer 31

``` cis= 2 pairs of ligands next to each other trans= 2 pairs of ligands opposite each other ```

Question 32

Cisplatin

Answer 32

PtCl2(NH3)2 - same group next to each other

Question 33

Cisplatin uses

Answer 33

1- treats cancer by stopping DNA unwinding so semi-conservative replication can't occur stopping tumours reproducing new cells 2-mechanisms triggered that cause cell death

Question 34

Cis-Trans Isomerism of Octahedral complex ions (6)

Answer 34

- occurs in 4 ligands of one type and 2 ligands of another type - 2-ligands opposite= trans - 2 ligands next = Cis

Question 35

Negative effects of Cisplatin

Answer 35

1- can bind to normal cells that replicate quickly like hair stopping them from replicating causing hair loss, suppress immune system. 2- damages Kidneys

Question 36

How to lessen side effects of Cisplatin

Answer 36

1- Very low dosages | 2-targeting cancer cells directly that only attacks healthy cells

Question 37

Why is Cisplatin as cancer treatments used despite adverse effects

Answer 37

balance of positive long term affects out weigh negative short term effects

Question 38

Ligand Substitution reaction

Answer 38

- at least 1 ligand swapped for another ligand | - results in colour change

Question 39

Substitution of similarly sized ligands

Answer 39

- ligands same size - co-ordination number of complex ions remains the same - Shape stays the same - colour changes

Question 40

Substitution of different sized ligands

Answer 40

- ligands different sizes - co-ordination number of complex ion changes - shape changes - colour changes

Question 41

Partial substitution of Ligands

Answer 41

- some ligands substituted partially - not all ligands substituted - colour changes

Question 42

Ligand exchange reactions can be easily reversed unless

Answer 42

unless the complex ion produced is much more stable than the old one

Question 43

if new ligands form stronger bonds with the central metal ion than the old ligands

Answer 43

change is less easy to reverse as new complex ion more stable

Question 44

Multidentate ligands form more stable ion complexes than monodentate ions so

Answer 44

the ligand exchange involving bidentate and multidentate ligands are hard to revers.

Question 45

Ligands in order of most stable to least

Answer 45

1- multidentate = most stable 2-bidentate 3-monodentate = least stable

Question 46

Enthalpy change for a ligand

Answer 46

1- very small | 2-because the strength of the bonds being broken is similar to the strength of the new bonds being made

Question 47

Entropy change for a ligand

Answer 47

1-when monodentate ligands are substituted by multi and bidentate ligands the number of particles increases 2-the more particles, the greater the entropy so reactions are more likely to occur 3-multi and bidentate are more stable than monodentate ligands 4-chelate effect

Question 48

chelate effect

Answer 48

1-when monodentate ligands substituted by bidentate and multidentate ligands it forms a more stable ion complex 2- particles number increases 3-entropy of system increases without enthalpy changing significantly 4-

Question 49

when multidentate ligand is substituted by bidentate or monodentate ligands

Answer 49

1- more stable complex ion formed 2-particle number increases 3-so entropy of system increases to a large and positive value without enthalpy changing significantly 4- AG decreases below zero so reaction feasible AG=AH-TAS

Question 50

Haeamoglobin

Answer 50

Fe(N)5(H2O) ---Oxygen----> Fe(N)5(O2) | deoxyhaemoglobin