CHEM214

Question 1

What are all of the d orbital labels?

Answer 1

dxy, dxz, dyz, dz^2, dx^2-y^2

Question 2

How many d orbitals are there?

Answer 2

5

Question 3

Which orbitals are negative in dxy?

Answer 3

those between the x&y axis

Question 4

Which orbitals are negative in dxz?

Answer 4

lobe on the top right along that diagonal

Question 5

Which orbitals are negative in dyz?

Answer 5

lobe on the top left and along diagonal

Question 6

Which orbitals are negative in dx^2?

Answer 6

central lobe

Question 7

Which orbitals are negative in dx^2-y^2?

Answer 7

along the y axis

Question 8

How are negative orbitals presented in diagrams?

Answer 8

shaded = negative

Question 9

What is the difference between shielding and penetration?

Answer 9

shielding = the inner shell core e- shield the nucleus, penetration = the outer e- penetrate the inner shells

Question 10

What electrons does shielding affect? Why?

Answer 10

• 1s has high ed so shields the 3d e- (and the rest of the orbitals) from the nucleus
• 2s shields 3d from the nucleus because the 3d maximum lies outside the 2s maximum
• the 4s does NOT shield 3d from the nucleus much because it is penetrating
• all s orbitals penetrate the core
• 4f electrons DO NOT shield 5s

Question 11

What electrons does penetration affect?

Answer 11

• the 3d penetrates the 2s
• 3d penetrates 4s very effectively due to lower principle quantum number and the 3d maximum lying inside the 4s maximum
• the 4s penetrates the core very effectively

Question 12

How does shielding and penetration depend on radial maxima?

Answer 12

• shielding occurs when the maximum of one orbital lies within the maximum of another
• small peaks in ed close to the nucleus allow an orbital to penetrate the core
• the higher the principle quantum number the less shielding an orbital is

Question 13

What is the effect of penetration?

Answer 13

• the outer electrons experiencing a higher than expected effective nuclear charge, which decreases the orbital energy
• the orbital doing the penetrating decreases in energy

Question 14

Does 3d or 4s fill first?

Answer 14

4s bc it’s at a lower energy

Question 15

What makes a transition metal a transition metal?

Answer 15

Its partially filled d shell

Question 16

What is the effect of a half-filled d shell?

Answer 16

extra stability

Question 17

Are 4s or 3d electrons lost first upon ionisation? Why?

Answer 17

4s bc at a higher energy due to the 3d penetrating the 4s so the 3d are at a lower energy

Question 18

What is the d-electron count?

Answer 18

the same as valence electron count - total of all electrons in the 3d and 4s orbitals

Question 19

Equation for d-electron count?

Answer 19

group number - oxidation state

Question 20

What are the pseudo transition metals? Why?

Answer 20

Sc, Cu and Zn, Cu has an incomplete d shell, but their chemistry is treated as if they are

Question 21

What is effective nuclear charge?

Answer 21

the amount of nuclear charge seen by an electron in that orbital

Question 22

What does the effective nuclear charge depend on?

Answer 22

the principle quantum number, shielding, and penetration

Question 23

What is the effect of the effective nuclear charge?

Answer 23

as Zeff increases, the orbital energy decreases

Question 24

What is the effect of shielding?

Answer 24

the Zeff of the e- being shielded decreases, so orbital energy increases

Question 25

What is the pattern of ion size across a period? Why?

Answer 25

ionic radius decreases across a period bc the Zeff increases

Question 26

Why do Mn, Fe, and Ni have higher ionic radius than expected?

Answer 26

effect of the partially filled d shell

Question 27

Why do 2nd and 3rd series elements have similar ionic radii?

Answer 27

lanthanide contraction - poor shielding of 5d e- by 4f`as the 4f orbitals are too diffused, 5d penetrate 4f very effectively so 5d has higher Zeff and contracts

Question 28

Are ligands lewis acids or bases?

Answer 28

lewis bases (electron pair donors)

Question 29

Are the metal atoms lewis acids or bases?

Answer 29

lewis acids (electron pair acceptors)

Question 30

How many electrons do the donor groups of ligands donate?

Answer 30

2

Question 31

What is the acetonitrile ligand?

Answer 31

MeCN

Question 32

What is the cyano ligand?

Answer 32

[CN-]

Question 33

What is the thiocyanate ligand?

Answer 33

[NCS]-

Question 34

What is the denticity?

Answer 34

the number of bonded groups in a ligand

Question 35

How many e- donated for bidentate ligands?

Answer 35

4e-

Question 36

Equations for calculating number of e- donated by a ligand?

Answer 36

=denticity*2 OR =number of donor groups*2

Question 37

What is the hapticity?

Answer 37

The number of atoms in the ligand, bonded to the metal

Question 38

How do pi-bonded benzene and sigma-bonded Ph donate different no. of e-?

Answer 38

pi-bonded benzene = 2e- from each bond = 6e- sigma-bonded Ph = 2e- only from one of the C not the C=C

Question 39

Charge of ammonia?

Answer 39

zero

Question 40

What is triethylphosphite?

Answer 40

P(OEt)3

Question 41

Charge of ethyl and phenyl?

Answer 41

-1

Question 42

What is polarizability?

Answer 42

how easy it is to distort the electron distribution/cloud of the donor

Question 43

Equation for charge density?

Answer 43

= charge/SA

Question 44

how polarisable is a hard ligand?

Answer 44

non polarisable (small, with a high charge, high oxidation state)

Question 45

how polarisable is a soft ligand?

Answer 45

highly polarisable (large, with a low charge, low oxidation state)

Question 46

What is the pattern with charge density and polarity?

Answer 46

higher charge density = the atom/ion is less polarisable and more polarising

Question 47

Are oxygen donors hard or soft?

Answer 47

hard

Question 48

Are phosphorus and sulfur donors hard or soft?

Answer 48

soft

Question 49

Is nitrogen hard or soft?

Answer 49

depends: ammonia = hard, pyridine = intermediate/soft (part of an unsaturated system)

Question 50

What are the typically hard metal ions?

Answer 50

first series TM with (III) oxidation state except Mn(II), Zn(II), and Ti(IV), Hf(IV), V(IV)

Question 51

Why is Ti(IV) a hard metal ion?

Answer 51

half-filled d shell (d5)

Question 52

What are the typically hard ligands?

Answer 52

F & Cl, H2O, [OH]-, ROH, R2O, [RCO2]-, [SO4]2-, [NO3]-, NH3, RNH2

Question 53

What are the typically intermediate metal ions?

Answer 53

1st series TM: Fe(II), Co(II), Ni(II), Cu(II) | Rh(III), Ir(III), Ru(III), Os(III)

Question 54

What are the typically intermediate ligands?

Answer 54

Br-, pyridine, [NCS]- = when binding through N

Question 55

What are the typically soft metal ions?

Answer 55

Cu(I), Ag(I), Au(I), Hg(II), Cd(II), Pd(II), Pt(II)

Question 56

What are the typically soft ligands?

Answer 56

I-, [CN]-, CO, PR3, RSH, R2S, [NCS]- = when binding through S

Question 57

Charge on CO?

Answer 57

neutral

Question 58

When is [NCS]- intermediate or soft?

Answer 58

intermediate if bonding through N, soft if bonding through S

Question 59

When is [NCS]- intermediate or soft?

Answer 59

intermediate if bonding through N, soft if bonding through S

Question 60

What type of ligand is CO?

Answer 60

Pi-acceptor so strong field

Question 61

What are some bidentate ligands?

Answer 61

acetoacetonate (acac), ethandioate, ethylenediamine

Question 62

how many e- do bidenentate ligands donate?

Answer 62

4e-

Question 63

how many e- do monodentate e- donate?

Answer 63

2e-

Question 64

how can carboxylate ligands bind?

Answer 64

either via one or both oxygens

Question 65

what spin a d e- is Co(III)

Answer 65

low spin d6 and high CFSE