Transition metals

Question 1

Do electrons fill up the 4s subshell or 3d subshell first?

Answer 1

4s (apart from in Chromium and Copper)

Question 2

Are electrons lost from the 4s subshell first, or the 3d shubshell?

Answer 2

4s subshell (apart from Cr and Cu)

Question 3

What is a transition metal?

Answer 3

Transition metals are metals which form stable ions with partially filled d-orbitals.

Question 4

What must ligands have?

Answer 4

a lone pair of electrons

Question 5

What type of bonds do ligands form with transition metals?

Answer 5

dative covalent bonds

Question 6

What is a ligand?

Answer 6

a molecule or ion with a lone electron pair which forms a dative covalent bond with a transition metal ion.

Question 7

What is a coordination number?

Answer 7

the number of dative covalent bonds (to a transition metal ion).

Question 8

What main factor determines the coordination number?

Answer 8

the size of each ligand (smaller ligands like NH3 can fit more around a transition metal ion, compared to larger ligands like Cl).

Question 9

When the overall charge of the complex ion is negative, the name of the metal changes to what?

Answer 9

to end in -ate.

(EG: iron becomes ferrate, chromium becomes chromate)

ion color

Question 10

What are three main factors that affect the colour of a transition metal complex?

Answer 10

• Oxidation state
• Ligand type
• The identity of the transition metal ion

Question 11

What is a ligand substitution reaction?

Answer 11

when at least one ligand replaces another.
(charge and coordination number can change depending on the ligand substituted (e.g: Cl- ligands will reduce the coordination number as they’re bigger and form a tetrahedral transition metal ion)).

Question 12

What is the colour change when excess HCl is added to a solution containing hexaaquacopper (II) ions [Cu(H2O)6]2+ ?

Answer 12

• the colour changes from light/pale blue to yellow-green.
• the complex ion [CuCl4]2- forms.

Question 13

What is the colour change for the ligand substitution:

[Cr(H2O)6]3+ + 6NH3 <=> [Cr(NH3)6]3+ + 6H2O

Answer 13

violet –> purple

Question 14

What is the colour change for the ligand substitution:

[Cu(H2O)6]2+ + 4NH3 <=> [Cu(NH3)4(H2O)2]2+ + 4H2O

Answer 14

pale blue –> dark blue.

Question 15

What colour is a Ti3+ ion?

Answer 15

violet/lilac.

Question 16

What colour is a V2+ ion?

Answer 16

violet/lilac.

Question 17

What colour is a V3+ ion?

Answer 17

green.

Question 18

What colour is a V4+ ion?

Answer 18

blue.

Question 19

What colour is a V5+ ion?

Answer 19

yellow.

Question 20

What colour is a Cr2+ ion?

Answer 20

blue.

Question 21

What colour is a Cr3+ ion?

Answer 21

green.

Question 22

What colour is a Cr6+ ion?

Answer 22

orange.

Question 23

What colour is a Mn2+ ion?

Answer 23

light pink.

Question 24

What colour is a Mn4+ ion?

Answer 24

dark pink/purple.

Question 25

What colour is a Mn6+ ion?

Answer 25

green.

Question 26

What colour is a Mn7+ ion?

Answer 26

violet/lilac.

Question 27

What colour is a Fe2+ ion?

Answer 27

light green.

Question 28

What colour is a Fe3+ ion?

Answer 28

yellow/green.

Question 29

What colour is a Co2+ ion?

Answer 29

pink.

Question 30

What colour is a Co3+ ion?

Answer 30

green.

Question 31

What colour is a Ni2+ ion?

Answer 31

green.

Question 32

What colour is a Cu2+ ion?

Answer 32

blue.

Question 33

What colour is a [Cr(H2O)6]3+ metal-aqua ion?

Answer 33

a violet solution (whenCr3+ reacts with NaOH or NH3).

Question 34

What colour is a [Fe(H2O)6]2+ metal-aqua ion?

Answer 34

a green solution (when Fe2+ reacts with NaOH or NH3).

Question 35

What colour is a [Fe(H2O)6]3+ metal-aqua ion?

Answer 35

a yellow solution (when Fe3+ reacts with NaOH or NH3).

Question 36

What colour is a [Mn(H2O)6]2+ metal-aqua ion?

Answer 36

a pale pink solution (when Mn2+ reacts with NaOH or NH3).

Question 37

What colour is a [Cu(H2O)6]2+ metal-aqua ion?

Answer 37

a blue solution (when Cu2+ reacts with NaOH or NH3).

Question 38

What colour is a Cr3+ ion with OH-? Cr(OH)3(H2O)3

Answer 38

green precipitate (whenCr3+ reacts with NaOH or NH3).

Question 39

What colour is a Fe2+ ion with OH-? Fe(OH)2(H2O)4

Answer 39

green precipitate (when Fe2+ reacts with NaOH or NH3).

Question 40

What colour is a Fe3+ ion with OH-? Fe(OH)3(H2O)3

Answer 40

brown precipitate (when Fe3+ reacts with NaOH or NH3).

Question 41

What colour is a Mn2+ ion with OH-? Mn(OH)2(H2O)4

Answer 41

pale brown precipitate (when Mn2+ reacts with NaOH or NH3).

Question 42

What colour is a Cu2+ ion with OH-? Cu(OH)2(H2O)4

Answer 42

blue precipitate (when Cu2+ reacts with NaOH or NH3).

Question 43

What colour is a Cr3+ ion with excess OH-? [Cr(OH)6]3-

Answer 43

green solution (whenCr3+ reacts with excess NaOH).

Question 44

What colour is a Cr3+ ion with excess NH3? [Cr(NH3)6]3+

Answer 44

a purple solution.

Question 45

What colour is a Cu2+ ion with excess NH3? [Cr(NH3)4(H2O)2]2+

Answer 45

a dark blue solution.