3.4 D block

Question 1

Define D block element

Answer 1

have their outer most electron in a full or partly full d orbital

Question 2

Define transition metal

Answer 2

have atoms or ions with a partly filled d d orbital

Question 3

properties of transition metals

Answer 3

• variable ox state
• form coloured compounds
• can react to form complex ions
• act as catalysts
  VCCC

Question 4

Discuss variable oxidation state

Answer 4

transition metals have partly filled d orbitals which easily loose or gain electrons (because they require small amounts of energy) which results in more than 1 ox state.

Question 5

What is a catalyst and what are the two types?

Answer 5

• substance which speeds up the rate of a reaction without being used up providing an alternative route lowering the activation energy.
• homogenous- same phase as reactants
• heterogenous- diff phase as reactants

Question 6

example of catalyst:
1) heterogenous

Answer 6

iron (Fe) in haber process N2 + 3H2 -> 2NH3

Question 7

example of catalyst:
2) heterogenous

Answer 7

nickel in hydrogenation of alkenes to alkanes

Question 8

example of catalyst:
3) heterogenous

Answer 8

MnO2 in decomposition of h2o2

Question 9

example of catalyst:
4) homogenous

Answer 9

V2o5 vanadium oxide in contact process
2s202 + o2 -> 2so3

Question 10

modes of catalyst: heterogenous

Answer 10

reactants adsorb onto to surface of a transition metal which allows and increase in collisions between reactants and the products deadsorp from the surface of the metal

Question 11

modes of catalyst: homogenous

Answer 11

work by transition metals changing ox state and allowing reaction to proceed with a lower ea

Question 12

How do catalysts work?

Answer 12

a) cuz tm have partly filled d orbitals they can accept/ release extra electrons e.g mno4- to mn2+
b) also cuz they have partly filled d orbitals they have spaces to act as docking stations for gas reactants to bind to and are held long enough for a reaction to happen and pop off as a new product.

Question 13

Define complex ion

Answer 13

when a tm ion binds using co-ordinate bonds to one or more ligands

Question 14

structure of complex ion

Answer 14

[ Cu(H20)6 ] 2+
ligand- brackets inside of square brackets
central tm ion- Cu

Question 15

Define ligand

Answer 15

a molecule or ion with a lone pair of electrons that form co-ordinate bonds with a tm ion which has a partially filled d orbital.

Question 16

Define co-ordination number

Answer 16

number of ligands that bond to a central tm ion

Question 17

How are coloured complexes formed?

Answer 17

• partially filled d orbitals arrange so that 3 are at lower energy than the other two
• there will be energy available for an electron to be promoted from lower to higher energy level but in doing so energy adsorbed from white light and remaining wavelengths reflect to give colour .

Question 18

colour changes with:

Answer 18

metal ion
ox state of ion
ligand bonded