Transition Metals

Question 1

D block

Answer 1

Elements where d shell level is the highest energy sub shell containing electrons

Question 2

Cr electron structure

Answer 2

[Ar] 4s 1 3d 5
Gives additional stability to atom half filled sub shell

Question 3

Cu electron structure

Answer 3

[Ar]4s1 3d10 full d orbital giving additional stability

Question 4

Transition elements

Answer 4

D block elements that form at least one ion with a partially filled d orbital
Sc and zinc aren’t (Sc loses 3e-) (Zn forms a full d orbital)

Question 5

Properties of trans metals and compounds

Answer 5

Form compounds which transition element has different oxidation states
Form coloured compounds
Act as catalysts

Question 6

Complex ions

Answer 6

One of most important properties of d block element
When one or more negatively charged ions bond to a central metal ion molecules are called ligands

Question 7

Ligand

Answer 7

A molecule or ion that donates a pair of electrons to form a coordinate bond

Question 8

Coordinate bond

Answer 8

When one of the bonded atoms provide both of the electron for the shared pair

Question 9

Coordination number

Answer 9

Number of coordinate bonds attached to the central metal ion

Question 10

Monodentate ligands

Answer 10

Donate one pair of electrons to a central metal ion

Question 11

Shapes of complex ions

Answer 11

Octahedral
Tetrahedral
Square planar

Question 12

Octahedral

Answer 12

The most common shape
6 coordinate bonds

Question 13

Tetrahedral

Answer 13

4 coordinate bonds
109.5 degrees
CuCl4 for example

Question 14

Square planar

Answer 14

4 coordinate bonds occurs in ions with 8 d electrons
90 degree bond angles

Question 15

Cis trans in complex ions

Answer 15

Most common in square planar complexes
Cis= 2 adjacent identical groups 90
Trans = 2 identical opp side 180

Question 16

Monodentate ligands in cos trans

Answer 16

Octahedral
90 degrees away = cis
180 degrees away = trans opposite side

Question 17

Bidentate ligands cis trans

Answer 17

Bidentate ligands adjacent = cis
Bidentate ligands are opp = trans

Question 18

Optical isomerism

Answer 18

Non superimposable mirror images of each other
Only possible with 3 Bidentate ligands 2 Bidentate + 2 mono
1 hexadentate ligand

Question 19

Ligand substitution

Answer 19

When one ligand is replaced by a different / another ligand in a complex ion

Question 20

Ligand sub with nh3 and [Cu(H20)6]^2+

Answer 20

Pale blue to dark blue solution
4 H20 ligands replaced by 4 NH3 ligands
Cu(OH)2 pp forms and then dissolved in excess ammonia

Question 21

Ligand substitution with Cl- (conc HCl)

Answer 21

Pale blue to yellow solution
6 H2O replaced by 4 Cl-
Octahedral -> square planar
Cl- ions are larger than H2O so fewer can fit round Cu 2+

Question 22

Reactions of Cr ions

Answer 22

Cr(H2O)6 ^3+ violet
Ammonia - Cr(OH)3 (grey/green) formed dissolves in excess ammonia -> purple

Question 23

Ligand sub in haemoglobin

Answer 23

Oxygen bonds to Fe2+ of haem group
Co2 also bonds to Fe2+
Carbon monoxide binds to form carboxyhaemoglonin which binds v strongly so ligand sun doesn’t occur
Oxygen cannot be picked up

Question 24

Precipitation reactions

Answer 24

When 2 aq sol containing ions react together to form an insoluble ionic solid

Question 25

Transition metals and precipitation

Answer 25

+ aq sodium hydroxide and aq ammonia Form pp Some may dissolve further to form complex ions

Question 26

Addition of NaOH ( insoluble)

Answer 26

Cu2+ blue sop to form insoluble blue pp Cu(OH)2 Fe2+ pale green sol form green pp Fe(OH)2 turns brown at surface Fe3+ pale yellow to form orange brown pp Fe(OH)3 Mn2+ pale pink to light brown pp Mn(OH)2

Question 27

Addition of NaOH ( soluble)

Answer 27

Cr3+ violet forms grey green pp Soluble in excess forming dark green solution -> [Cr(OH)6]^3-

Question 28

Further addition of ammonia

Answer 28

Cu(OH)2 -> [Cu(NH3)4(H2O)2]2+ blue pp to deep blue sol Cr(OH)3 -> [Cr(NH3)6]^3+ green pp to purple solution Fe2+,Fe3+ and Mn2+ react with excess ammonia forming pp of Fe(OH)2 for example

Question 29

Iodine thiosulphate equation

Answer 29

2S2O3 2- + I2 => 2I- + S4O6 2- Starch black blue to colourless

Question 30

S2O3 2-

Answer 30

Thiosulphate ions are oxidised lose 2e- 2 per I2 1:1 thiosulphate ions to iodide ions I-

Question 31

I2

Answer 31

Iodine is reduced Gains 2e-

Question 32

Thiosulphate ratios

Answer 32

1:1 ratio = Cu 2+ : S2O3 2- S2O3 2- : I- 2:1 ratio= S2O3 2- : I2