Transition Metals

Question 1

Transition Metals

Answer 1

D block elements that can form one or more stable ions with incompletely filled d orbitals

Question 2

When ions are formed

Answer 2

S electrons are removed first

Question 3

Sc and Zn aren’t transition metals

Answer 3

Sc- Only forms one ions- Sc3+ Which has an empty d sub shells (Ar)
Zn- Only forms one ion, Zn2+ which has a full d sub shell (Ar) 3d104s2

Question 4

Transition Metlas

Answer 4

Have variable oxidation states
To form a compound or complex containing an ion with a certain oxidation number, the energy given out when the ion forms a compound or a complex needs to be greater than the energy taken to remove the outer electrons and form the ion (ionisation energy)

Question 5

Transition metals- Why variable ox states

Answer 5

Form by losing electrons from both their 4s and 3D au shells- Similar energy levels so it takes a similar amount of energy to remove an electron from the 4s au shell

Question 6

The energy released when ions from a complex or compound increase

Answer 6

With ionic charge- Therefore the increase in the energy required to remove outer electrons to form transition metal ions with higher oxidation numbers is usually counteracted by the increase in energy released

Question 7

Complex ions

Answer 7

Metal ion surrounded by dative covalent bonded Kiyan’s

Question 8

Ligand

Answer 8

Atom. Ion or molecule that donates a pair of electrons to a central metal atom or ion

Question 9

Bidentate

Answer 9

1,2-diaminoethane

Question 10

Multidentate

Answer 10

Ligands with more than 2 lone pairs- EDTA4- has six lone pairs

Question 11

Coordination no

Answer 11

No. Dative covalent bonds formed with the central metal ion

Question 12

Complexes with four fold coordination

Answer 12

Tetrahedral- [CuCl4]2-
109.5 degrees

Question 13

Square planar

Answer 13

Cis platin
90 degree angles
Pt
Ni

Question 14

Complex ions and colour - y?

Answer 14

Usually 3D orbitals have same energy
Ligand binds to ions
3D orbitals split into 2 different energy levels
Electrons tend to occupy lower
To jump, need energy equal to energy gap- Visible light
Amount of energy needed to make electrons jump depends on central metal ion and oxidation number of ligands

Question 16

Colour

Answer 16

Rest of frequencies of light are transmitted
These transmitted combine to make complement go colours absorbed

Question 17

MnO4-

Answer 17

Purple

Question 18

Cr2O72-

Answer 18

Orange

Question 19

Cr3+

Answer 19

Green

Question 20

YBGV

Answer 20

5-4-3-2

Question 21

Fe3+

Answer 21

Yellow

Question 22

Fe2+

Answer 22

Pale green

Question 23

CO2+

Answer 23

Pink

Question 24

Cu2+

Answer 24

Pale blue

Question 25

Chromium Ions

Answer 25

6+- Cr2O7^2- Orange

Question 26

Chromium (3) ions- [Cr(H2O)6]3+

Answer 26

React with alkaline or acid- Both get chromium hydroxide precipitate [Cr(OH)3(H2O)3] - Grey green precipitate

Question 27

Grey green precipitate - [Cr(OH)3(H2O)3

Answer 27

Amphoteric- React with acid or with base

Question 28

Add excess sodium hydroxide to a chromium hydroxide precipitate,

Answer 28

H2O ligands deprotonate and solution containing [Cr(OH)6]3- forms- Dark green solution

Question 29

Add acid to chromium hydroxide precipitate,

Answer 29

OH- ligands protonate and a solution containing [Cr(H2O)6]3+ forms

Question 30

Add excess ammonia to chromium hydroxide precipitate- Ligand reaction occurs.

Answer 30

Grey green precipitate + 6NH3-> [Cr(NH3)6]3+- Purple solution + 3OH- + 3H2O

Question 31

Catalysts

Answer 31

Good because they can change oxidation number by gaining or losing electrons within their d orbitals - They can transfer electrons to speed up reactions

Question 32

Contact Process

Answer 32

SO2 is oxidised to SO3 V2O5 + SO2-> V2O4 + SO3 V2O4 + 1/2O2-> V2O5

Question 33

Autocatalysis

Question 34

Homogeneous Catalysts

Question 35

Positive Entropy- Makes more stable compound

Answer 35

Ligand échange réaction Dative bonds are broken and formed Strength of the bonds broken is often very similar to the strength of the new bonds being made- Enthalpy change for this reaction is very small

Question 36

Reactions of ligands

Question 37

Ligands exchanging

Question 38

Monodentate ligands

Answer 38

Substituer with bidentate or muktidentate- no particles in solution increases- greater entropy- more likely to occur

Question 39

Hexadentate ligand

Answer 39

Replaces monodentate or bidentate ligands, complex formed is more stable

Question 40

CrO4^2-

Answer 40

Yellow 6+

Question 41

Cr^3+

Answer 41

3+ Green (Violet)

Question 42

Cr^2+

Answer 42

2+ Blue

Question 43

Chromium 6+ reduction

Answer 43

Reduced using a reducing agent such as zinc and dilute acid Cr2O7^2- + 14H+ + 3Zn-> 3Zn^2+ + 7H2O + 2 Cr^3+

Question 44

Cr^3+ Reduction

Answer 44

2Cr^3+ + Zn -> Zn^2+ + 2Cr^2+

Question 45

Oxidation of Cr3+ to Cr6+

Answer 45

2Cr^3+ + 10 OH^- + 3 H2O2-> 2CrO4^2- + 8 H2O Alkaline solution Hydrogen Peroxide- Oxidation

Question 46

Adding acid to Yellow solution- CrO4^2-

Answer 46

2CrO4^2- + 2H+ ->Reversible reaction -> Cr2O7^2- + H2O Gives orange solution