Unit 3: Coordination Chemistry

Question 1

What are the similar properties of transition metals?

Answer 1

• Relatively high electrical conductivity
• Relatively high thermal conductivity
• More than 1 oxidation state
• Often form complex ions
• Most can absorb visible light
• Many compounds are paramagnetic

Question 2

What are the different properties of transition metals?

Answer 2

• Melting points
• Hardness
• Oxides

Question 3

What groups follow the stability rule in regard to electron configuration?

Answer 3

Group 6 and group 11

Question 4

What makes up a coordination compound?

Answer 4

It is made of a complex ion and counter ions.

Question 5

What is coordination numbers?

Answer 5

The number of bonds from the ligands to the central metal atom.

Question 6

What are counter ions?

Answer 6

Ions which are needed to maintain charge neutrality of the compound.

Question 7

What shape forms from a coordination # = 2?

Answer 7

Linear, is the least common shape.

Question 8

What shape forms from a coordination # = 4?

Answer 8

Square planar or tetrahedral

Question 9

What shape forms from a coordination # = 6?

Answer 9

Octahedral, most common

Question 10

How can you determine whether a CN of 4 will be square planar or tetrahedral?

Answer 10

If the electron configuration of the metal is nd8 the shape will most likely be square planar.
For all other metals, it will be tetrahedral.

Question 11

What is a ligand?

Answer 11

It is a neutral molecule or an ion with a lone pair of e-‘s

Question 12

What is a monodenate/unidentate ligand?

Answer 12

It is attached to the metal by one bond.

Question 13

fluoro

Answer 13

F-

Question 14

chloro

Answer 14

Cl-

Question 15

bromo

Answer 15

Br-

Question 16

iodo

Answer 16

I-

Question 17

cyano

Answer 17

CN-

Question 18

hydroxo

Answer 18

OH-

Question 19

aqua

Answer 19

H20

Question 20

ammine

Answer 20

NH3

Question 21

carbonyl

Answer 21

CO

Question 22

nitrosyl

Answer 22

NO

Question 23

Polydentate lignads?

Answer 23

Attached to metal by more than 1 bond or pair of electrons.

Question 24

Bidentate?

Answer 24

2 pairs e-

Question 25

ethylenediamine

Answer 25

en

Question 26

oxalate

Answer 26

ox2-

Question 27

How do you name a complex ion?

Answer 27

1. Cation named before anion 2. Name ligands before metal 3. Use prefixes for ligands 4. Designate the oxidation # of metal using Roman numerals

Question 28

What is different about period 4 transition metals?

Answer 28

They are active enough to reduce H+ from acid solution.

Question 29

What are the two main types of isomers?

Answer 29

Structural isomers and stereoisomers.

Question 30

What are the two types of structural isomers?

Answer 30

Coordination isomers - Ligand and counter-ion exchange Linkage isomers - Different donor atom

Question 31

What are the two types of stereoisomers?

Answer 31

Geometric isomers - Different arrangements around the metal ion Optical isomers - non-superimposable mirror images

Question 32

What are the bond names for SCN-?

Answer 32

via sulfur: thiocyanato via nitrogen: isothiocyanato

Question 33

What are the bond names for OCN-?

Answer 33

via oxygen: cyanato via nitrogen: isocyanato

Question 34

What are the bond names for NO2-?

Answer 34

via nitogen: nitro via oxygen: nitrito

Question 35

What is a cis geometric isomer?

Answer 35

Identical ligands are 90* apart.

Question 36

What is a trans geometric isomer?

Answer 36

Identical ligands are 180* apart

Question 37

What is a facial geometric isomer?

Answer 37

All 3 identical ligands are 90* apart

Question 38

What is a meridional geometric isomer?

Answer 38

2 identical ligands are 180* apart and 1 identical ligand is 90* apart from the other 2.

Question 39

What is the crystal field theory?

Answer 39

It is a bonding model which explains the properties of transition metals.

Question 40

What is the eg set?

Answer 40

dz2, dx2-y2 The orbital energy goes up (destabilized) The ligand lone pair is aligned with the orbital

Question 41

What is the t2g set?

Answer 41

dxy, dxz, dyz The orbital energy goes down (stabilized) The ligand lone pair is between orbitals

Question 42

What is a free ion?

Answer 42

d-orbitals have same energy (degenerate)

Question 43

Crystal field splitting?

Answer 43

Energy splitting, explains the magnetic properties of transition metals.

Question 44

What happens if the crystal field splitting is small?

Answer 44

- Pairing is not favorable - e- will fill t2g and eg sets before pairing - Forms high-spin complexes - High # of unpaired e-

Question 45

What happens if the crystal field splitting is large?

Answer 45

- Pairing is favorable - e- will fill t2g set first then eg set - Forms low-spin complexes - Low # of unpaired e-

Question 46

Does the magnitude of the crystal-splitting energy increase with the more valance e-?

Answer 46

Yes

Question 47

What is a diamagnetic species?

Answer 47

Not attracted to a magnetic field and all electrons are paired.

Question 48

What is a paramagnetic species?

Answer 48

Attracted to a magnetic field and has unpaired electrons.

Question 49

Why do we observe colours in transition metals?

Answer 49

The splitting of energy splits the d-orbital into 2 levels, which causes energy to be absorbed. We see the colour is the opposite of the wavelength absorbed.