transition metal ions in solution colours

Question 1

define transition metals

Answer 1

d -block elements that forms stable ions with a partially filled d-orbital

Question 2

3 properties of transition elements

Answer 2

-their elements and compounds may act as catalysts
-they form coloured compounds
-they have different oxidation states e.g. Fe2+/Fe3+

Question 3

Transition elements sub shell rule
what are the exceptions?

Answer 3

• 4S orbital empties before the 3d orbital
• 4S orbital fills before the 3d orbital

exceptions:
copper-[Ar] 4s13d10
chromium- [Ar] 4s13d5

Question 4

blue colour compounds

Answer 4

V 4+
Cr 2+
Cu 2+

Question 5

green colour compounds

Answer 5

V 3+
Cr 3+
Co 3+
Ni 2+
Mn 6+

Question 6

purple colour compounds

Answer 6

V 2+
Mn 7+
Ti 3+

Question 7

yellow colour compound

Answer 7

V 5+

Question 8

pink colour compounds

Answer 8

Mn 2+( light pink)
Mn 4+ ( purple-pink)
Co 2+ (dark pink)

Question 9

orange colour compound

Answer 9

Cr 6+

Question 10

cream colour compound

Answer 10

Fe 3+

Question 11

pale green colour compound

Answer 11

Fe 2+

Question 12

ligand

Answer 12

molecule/ion with a lone pair that forms a dative covalent bond with a transition metal ion

Question 13

co ordination number

Answer 13

number of dative covalent bonds

Question 14

complex ion

Answer 14

central metal surrounded by ligands

Question 15

difference between monodentate and bidentate ligands

Answer 15

unidentate- donates one lone pair to central metal ion forming one dative/co-ordinate bond
bidentate- donates two lone pairs and forms two co-ordinate binds with central metal ion

Question 16

examples of monodentate ligands

Answer 16

Cl-, H2O, OH-

Question 17

examples of bidentate ligands

Answer 17

1,2-diaminoethane
ethanodioate ion

Question 18

transition metal ions that form square planar shapes

Answer 18

Ni
Pd
Pt( cis platin)

Question 19

how does cisplatin treat cancer?
note- transplatin cannot treat cancer

Answer 19

binds to DNA and prevents them from dividing uncontrollably(2 chlorides lost)
Has severe side effects because it also binds to DNA in healthy cells

Question 20

cis isomer

Answer 20

two ligands 90 degrees away fron eachother

Question 21

trans isomer

Answer 21

two ligands 180 degrees opposite from eachother

Question 22

How does cisplatin treat cancer?
note: transplatin has no effect on cancer

Answer 22

-Cisplatin binds to DNA in cancer cells and stops them from dividing uncontrollably(2 chlorides lost)
severe side effects on kidney because it also binds to DNA in healthy cells.

Question 23

ligand substitution reaction

Answer 23

when at least one ligand replaces another ligand

Question 24

whenever bidentate ligands substitute monodentate ligands….

Answer 24

entropy increases because there are more particles in the products than reactants.
there is more disorder with more particles in the system
known as chelate effect

Question 25

what is a haem group?
How does ligand substitution in haemoglobin work?

Answer 25

-Haem is a multidentate ligand which forms 4 coordinate bonds with a Fe2+ ion . Oxygen binds to Fe2+. when blood cells reach areas of the body that needs oxygen, oxygen is released and replaced with a water ligand

Question 26

explain carbon monoxide poisoning

Answer 26

carbon monoxide forms strong coordinate and stable, permanent bond with haemoglobin so it cannot be replaced by carbon dioxide, oxygen or water by ligand substitution. This makes the haemoglobin useless.

Question 27

catalyst

Answer 27

A catalyst is a substance that increases the rate of a reaction without being used up in the reaction.

Question 28

heterogenous and homogeneous catalyst

Answer 28

-heterogenous- different phase from reactants
-homogeneous-same phase as reactants

Question 29

Haber process

Answer 29

Reaction: N2 (g) + 3H2 (g) ⇌ 2NH3 (g)

Catalyst: Fe (s)

Type of catalysis: heterogeneous

How does the catalyst work: provides a surface upon which the reaction can occur with a lower activation energy

Question 30

hydrogen peroxide decomposition

Answer 30

2H2O2(aq)—–> 2H2O(l)+O2(g)
type of catalyst- h

Question 31

Peroxydisulfate and Iodide

Answer 31

Reaction: S2O82- (aq) + 2I- (aq) → 2SO42- (aq) + I2 (aq)

Catalyst: Fe2+ (aq)

Type of catalysis: homogeneous

How does the catalyst work:

S2O82- (aq) + 2Fe2+ (aq) → 2SO42- (aq) + 2Fe3+ (aq)

2Fe3+ (aq) + 2I- (aq) → 2Fe2+ (aq) + I2 (aq)

Question 32

contact process

Answer 32

Reaction: 2SO2 (g) + O2 (g) ⇌ 2SO3 (g)

Catalyst: V2O5 (s)

Type of catalysis: heterogeneous

How does the catalyst work:

SO2 (g) + V2O5 (s) → SO3 (g) + V2O4 (s)

V2O4 (s) + O2 (g) → V2O5 (s)

Question 33

metal aqua ions

Answer 33

complex ions that only contain water ligands

Question 34

name the 5 metal aqua ions and their solution colours
they all have X(H2O)6
water ligands have 0 charge so the overall charge will be included on the metal ion

Answer 34

-Fe2+ = green
-Cu2+ = blue
-Mn2+ = pink
-Fe3+ = yellow/purple
-Cr 3+ = violet/green

Question 35

precipitation reaction

Answer 35

occurs when two aqueous solutions containing ions react together to produce an insoluble ionic solid

Question 36

precipitation reaction colours of transition metal hydroxides

Question 37

test for NH4+ cation

Answer 37

-gently heat NaOH
-react with warm NaOH to form NH3(g)
Red litmus paper turns blue to test for NH3 gas

Question 38

test for NH3(g)

Answer 38

red litmus paper turns blue

Question 39

MnO4- colour

Answer 39

purple in solution

Question 40

what are the two manganate (MnO4-) titrations

Answer 40

-Iron(II) Fe 2+
- ethandioic acid C2O4 2- / (COOH)2
purple to colourless

Question 41

Mn 2+ colour

Answer 41

colourless

Question 42

how are H+ ions provided in potassium manganate redox titrations

Answer 42

HCL