Transition Elements

Question 0

Which two elements are odd in their electronic configuration?

Answer 0

Copper and chromium

Question 1

What 3 properties do transition metals have?

Answer 1

Elements of the d-block that have

• partially filled d-orbitals
• can form complexes by coordinate bonding
• have several different oxidation states (both 4s and 3d e- are easily lost as orbitals are very close)

Question 2

What are copper and chromium’s electronic configuration?

Answer 2

Cu) 3d10 4s1

Cr) 3d5 4s1

Question 3

What are the oxidation states of manganese?

Answer 3

+2 +4 +7

Question 4

What is a ligand?

Answer 4

A small molecule with a lone pair that an coordinate bond to a transition metal ion

Question 5

What shape is a complex with 2 ligands?

Give an example

Answer 5

Linear

Ag(NH3)2 +

Question 6

What shape is a complex with 4 ligands?

e.g.?

Answer 6

Tetrahedral

(CuCl4)2-

Question 7

What are the bond angles in a complex with 4 ligands?

Answer 7

109.5°

Question 8

Complexes with 6 ligands form what shape?

e.g.?

Answer 8

Octahedral

Cu(NH3)4(H2O)2 2+

Question 9

What colour is aqueous Cu2+ ?

Answer 9

Pale blue

Question 10

If NH3 (aq) is added to Cu2+ (aq) what is formed and what colour is it?

Answer 10

Cu(NH3)4(H2O)2 2+

Royal blue

Question 11

When HCl(conc) is added to Cu2+ (aq) what is formed and what colour is it?

Answer 11

(CuCl4)2-

Yellow green

Question 12

Why are some ions not colourful?

Answer 12

If it has full (Cu+) or empty (Ti4+) d-orbitals then electrons cannot move between energy levels
-> appears colourless/white

Question 13

What is the colour of aqueous Cr3+?

Answer 13

Green

Question 14

What is the colour of aqueous Fe2+?

Answer 14

Pale green

Question 15

What is the colour of aqueous Fe3+?

Answer 15

Yellow

Question 16

What is the colour of aqueous Cu2+ with NaOH(aq)

Answer 16

Pale blue ppt

Question 17

What is the colour of aqueous Fe3+ when added to NaOH(aq)

Answer 17

Red brown ppt

Question 18

What is the colour of aqueous Fe2+ when added to NaOH(aq)

Answer 18

Dark green ppt

Question 19

What is the colour of aqueous Cr3+ when added to NaOH(aq)

Answer 19

Grey green ppt

Question 20

Which of these ppts redissolve with excess NaOH (aq) ?

Answer 20

Cr(OH)3 ppt -> (Cr(OH)6)3-

Green solution

Question 21

Why are transition elements good catalysts?

Answer 21

Their partially filled d-orbitals can form coordinate bonds with reactant molecules.
Their variable oxidation states can reduce or oxidise the reactant to make them more reactive.

Question 22

3 examples of a transition metal acting as a catalyst?

Answer 22

Iron in the Haber Process
Nickel in the catalytic cracking of hydrocarbons
Vanadium(V)oxide in the contact process

Question 23

Give two examples of transition metals’ importance in industry

Answer 23

Chromium in stainless steel
Iron in construction
Copper in circuitry and electronics