Transition metals

Question 1

Write the electronic config of a Cu atom

Answer 1

[Ar]3d104s1

Question 2

write the electronic config of a Fe2+ ion

Answer 2

[Ar]3d6

Question 3

write the electronic config of a Fe3+ ion

Answer 3

[Ar]3d5

Question 4

give the definition of a transition metal

Answer 4

A transition metal is one which forms one or more ions with partially filled d orbitals. That
would exclude scandium which only forms 3+ ions with the 3d level empty, and zinc which
only forms 2+ ions with the 3d level full.

Question 5

Explain why iron can form a 3+ ion whereas calcium only forms a 2+ ion

Answer 5

The third ionisation energy of calcium is much greater than the third ionisation energy of
iron. In the calcium case, the gain in lattice enthalpy or hydration enthalpy in forming the 3+ ion
isn’t enough to compensate for the higher ionisation energy. In the iron case, it is.

Question 6

What is the general name given to groups such as water, ammonia or chloride ions which
surround the central metal ion?

Answer 6

ligands

Question 7

What colours are the [Cu(H2O)6]
2+ and [Cu(NH3)4(H2O)2]
2+ ions

Answer 7

[Cu(H2O)6]2+ –>pale blue

[Cu(NH3)4(H2O)2]2+ –>very dark blue

Question 8

Name the catalyst in the Haber Process for the manufacture of ammonia.

Answer 8

Iron

Question 9

explain how complex ions can absorb certain frequencies of light

Answer 9

The water molecules increase the energy of all the d orbitals, but there is now an energy gap
within the d orbitals, with two of the orbitals having a higher energy than the other three. If light of
the right frequency (and therefore energy) falls on the ion, an electron from the lower energy
orbitals can be promoted into the space in the higher energy orbital.

Question 10

why are Zn2+ ions colourless

Answer 10

Does not have a partially filled d sublevel- there is no space in higher orbitals to promote electrons into

Question 11

write a general equation for the reaction of a metal hexaaquaion with ammonia

Answer 11

[M(H2O)6}2+ + 2(NH3)–>[M(H2O)5(OH)] + 2(NH4+)

Question 12

write the equation, with excess ammonia

Answer 12

[M(H2O)6]+ 4(NH3) –> [M(H2O)2(NH3)4]2+ + 2H20

Question 13

how does the reaction of 2+ complex ions with carbonate ions differ to the reaction with 3+ ions

Answer 13

With 3+ ions, you get the complex ion e.g. [M(H2O)3(OH)3] (remember 2:3:2:3:3). With 2+ ions, you get the metla carbonate e.g. MCO3

Question 14

What is a Bronsted-Lowrey base?

Answer 14

A substance that accepts protons

Question 15

What is a Lewis base?

Answer 15

A substance that is able to donate a lone pair

Question 16

what is a multidente ligand

Answer 16

ligands with a number of atoms capable of donating an electron pair producing several coordiante bonds

Question 17

what is entropy

Answer 17

a measure of disorder

Question 18

what sign should deltaG have for the reaction to be feasible

Answer 18

deltaG must be negative

Question 19

why are tetrahedral complexes formed with Cl- ions

Answer 19

because Cl- ions are so big, only 4 bonds can fit around the central ions e.g. 4 cl ions bond with a central Co atom

Question 20

give an example of a linear complex

Answer 20

[Ag(NH3)2]+

Question 21

give an equation summarising the energy absorbed by bond when an electron moves from its ground state

Answer 21

deltaE=hv (h=planks constant)

Question 22

what factors will determine the colour of the ion complex

Answer 22

ligands
coordination number
oxidation state of metal

Question 23

how can you measure the concentration of metal ion complexes

Answer 23

using a colourimeter

Question 24

what is the catalyst used in the contact process for the manufacture of sulphuric acid

Answer 24

V2O5

Question 25

what is the reaction that takes place during the contact process

Answer 25

So2+V2O5–>So3+V2O4

Question 26

what are heterogeneous catalysts

Answer 26

catalysts that are in a different phase to the reactants

Question 27

give an example of a good metal catalyst

Answer 27

Platinum

Question 28

what is the catalyst used in the Habor process for the production of ammonia

Answer 28

Iron

Question 29

why is a honeycomb structure of the catalyst often used

Answer 29

to maximise surface area- greater area=more likely for reactants to collide with the catalyst

Question 30

what is the intermediate species produced during stage 1 of the reaction between I- and S2O82-

Answer 30

Fe3+

The Fe3+ ion is then reacted with the I- ion to form I2 and Fe2+

Question 31

write the two half equations that when combined, give the overall equation for the reaction of C2O42- with MnO4-

Answer 31

MnO4- + 8H+ + 5e- –> Mn2+ + 4H2O

C2O42- –> 2CO2 + 2e-