transition metals

Question 1

colour of [Cu(H2O)6]2+ in solution

Answer 1

light blue solution

Question 2

colour of Cu(OH)2

Answer 2

blue precipitate

Question 3

colour of [Cu(NH3)4(H2O)2]2+

Answer 3

dark blue solution

Question 4

colour of [CuCl4]2-

Answer 4

yellow solution

Question 5

colour of [Fe(H2O)6]2+

Answer 5

green solution

Question 6

colour of Fe(OH)2

Answer 6

green precipitate

Question 7

colour of [Fe(H2O)6]3+ in solution

Answer 7

yellow solution

Question 8

colour of Fe(OH)3

Answer 8

orange-brown precipitate

Question 9

colour of [Mn(H2O)6]3+

Answer 9

pale pink solution

Question 10

colour of Mn(OH)2

Answer 10

light brown precipitate

Question 11

colour of [Cr(H2O)6]3+

Answer 11

violet solution

Question 12

colour of [Cr(H2O)5SO4)]+

Answer 12

green solution

Question 13

colour of Cr(OH)3

Answer 13

grey-green precipitate

Question 14

colour of [Cr(NH3)6]3+

Answer 14

purple solution

Question 15

colour of [Cr(OH)6]3-

Answer 15

dark green solution

Question 16

what does chrom alum, KCr(SO4)2.12H2O, make?

Answer 16

[Cr(H2O)6]3+

Question 17

what does chromium sulphate, Cr2(SO4)3, make?

Answer 17

[Cr(H2O)5SO4)]+

Question 18

what is a transition metal?

Answer 18

elements that form stable ions with a partially filled d sub shell

Question 19

what is a ligand?

Answer 19

any molecule/ion that can donate a pair of electrons to a central metal ion, forming a dative covalent bond

Question 20

what is a complex?

Answer 20

formed when one or more molecules/anions bond to a central metal ion

Question 21

what are the properties of transition metals?

Answer 21

they are good catalysts, as they have variable oxidation states
their ions formed coloured precipitates

Question 22

what is a coordination number?

Answer 22

the number that indicated the number of coordinate bonds attached to the central metal ion

Question 23

if the coordination number of a complex is 6, what shape will it have?

Answer 23

octahedral

Question 24

if the coordination number of a complex is 4, what shape will it have?

Answer 24

square planar or tetrahedral

Question 25

what is the electron configuration of copper and why is this the case?

Answer 25

4s1 3d10 instead of 4s2 3d9
this is because having the same number of electrons in each d orbital gives more stability to the metal

Question 26

what is the electron configuration of copper and why is this the case?

Answer 26

4s1 3d5 instead of 4s2 3d4
this is because having the same number of electrons in each d orbital gives more stability to the metal

Question 27

explain why Sc and Zn are not transition metals

Answer 27

Sc: only stable ion is Sc3+ which does not have a partially filled d sub shell
Zn: only stable ion is Zn2+ which does not have a partially filled d sub shell

Question 28

what is the mnemonic for the preferred charges of the transition metals?

Answer 28

All Good Boys Get To See It Is On TV
Sc Ti V Cr Mn Fe Co Ni Cu Zn
where the number of letters in the mnemonic corresponds to the preferred charge of the metal

Question 29

why does the 4s sub shell fill up before the 3d sub shell?

Answer 29

the 4s sub shell is at a lower energy level than the 3d sub shell, so it fills first

Question 30

what is the equation for the reaction of Cu2+ (aq) and dropwise NH3?

Answer 30

1. NH3 + H2O —> NH4+ + OH-
2. [Cu(H2O)6]2+ + 2OH- —> Cu(OH)2 + 6H2O
3. Cu(OH)2 + 4NH3 + 2H2O —> [Cu(NH3)4(H2O)2]2+ + 2OH-

Question 31

what is the equation for the reaction of Cr3+(aq) and dropwise NH3?

Answer 31

1. NH3 + H2O —> NH4+ + OH-
2. [Cr(H2O)6]3+ + 3OH- —-> Cr(OH)3 + 6H2O
3. Cr(OH)3 + 6NH3 —> [Cr(NH3)6]3+ + 3OH-

Question 32

what is the equation for the reaction of Cr3+(aq) and dropwise NaOH?

Answer 32

1. [Cr(H2O)6]3+ + 3OH- —-> Cr(OH)3 + 6H2O
2. Cr(OH)3 + 3OH- —> [Cr(OH)6]3-