Transition Elements

Question 1

Fe 2+ with NaOH

Answer 1

Fe(OH)2

Pale green to dark green ppt

Question 2

Fe 3+ with NaOH

Answer 2

Fe(OH)3

Pale yellow to brown ppt

Question 3

Mn 2+ with NaOH

Answer 3

Mn(OH)2

Pink to pale brown ppt

Question 4

Cu 2+ with NaOH

Answer 4

Cu(OH)2

Pale blue to blue ppt

Question 5

Cr 3+ (aq) with excess NaOH (2 step)

Answer 5

Cr(OH)3
Cr(OH)6
Violet soloution to grey green ppt to dark green soloution

Question 6

Cr3+ with excess NH3 (2 step)

Answer 6

Cr(OH)3
Cr(NH3)6
Violet soloution to grey green ppt to purple soloution

Question 7

Cu2+ with excess NH3 (2 step)

Answer 7

Cu(OH)2
Cu(NH3)4(H2O)2
Pale blue soloution to blue ppt to dark blue soloution

Question 8

Cu2+ with Cl ions

Answer 8

Cu(Cl)4
Pale blue soloution to yellow soloution
(Mixture is green)

Question 9

Cr2+

Answer 9

Pale blue

Question 10

KCr(SO4)2 dissolved in water

Answer 10

Cr(H20)6

Violet

Question 11

What is a dblock element?

Answer 11

Highest energy electrons In d orbitals

Question 12

List some properties of transition metals?

Answer 12

Metallic, high mp and no , shiny ,conductive

Question 13

How and why do chromium and coppers electron configuration differ to other transition metals?

Answer 13

They don’t pair in the 4s orbital as having a half filled d5 sub shell or filled d10 sub shell increases the stability of the atoms

Question 14

When is the 4s orbital filled and empties in d-block ions

Answer 14

Filled first, emptied first

Question 15

Definition for transition metals

Answer 15

D block elements that form at least one ion with a partially filled d subshell

Question 16

Why are Scandium and zinc not classified as transition metals

Answer 16

The only ions they form don’t have partially filled d sub shell

• Sc^3+
• Zn^2+

Question 17

List 3 properties of transition metal compounds

Answer 17

• Form compounds in which transition metal has different oxidation states
• coloured compounds
• act as catalysts

Question 18

What oxidation number can all the transition elements have ?

Answer 18

2+

Question 19

What colour is K2Cr2O7

Answer 19

Orange

Question 20

Give 3 examples of Transition metals acting as catalysts in industry?

Answer 20

• Iron in the Haber process (ammonia production)
• V2O5 in the contact process (SO3 production)
• Nickel in hydrogenation of vegetable fat for margarine

Question 21

What is a heterogeneous catalyst

Answer 21

Catalyst in a different state to reactants

Question 22

What is a homogeneous catalyst

Answer 22

Catalyst in the same state as the reactants

Question 23

What is a complex ion

Answer 23

One or more ligands bonded with dative covalent bonds to a central metal ion

Question 24

What is a ligand

Answer 24

A molecule or ion that donates a pair of electrons to a central metal ion to form a dative covalent bond/ coordinate bond

Question 25

What is coordination number

Answer 25

Number of coordinate bonds attached to central metal ion

Question 26

What is a monodente ligand

Answer 26

Ligand that donates one pair of e to a central metal ion

Question 27

3 Examples of monodente ligands?

Answer 27

Eg: H2O: , :NH3 , :Cl- , :CN- , :OH-

Question 28

What is a Bixente ligand?

Answer 28

Donate two lone pairs of e to central metal ion

Question 29

What are the two common bidente ligands

Answer 29

``` 1,2-diaminoethane (shortened to en) Ethanediote ion (COO)2 ```

Question 30

What is the shape and bond angle of a complex ion with coordination number 6?

Answer 30

Octahedral , 90*

Question 31

What is the shape and bond angle of most complex ions with four coordinate bonds?

Answer 31

Tetrahedral 109.5*

Question 32

Give two examples of a tetrahedral ion

Answer 32

CoCl4 , CuCl4 (both have 2 minus charge)

Question 33

What is the shape and bond angle for a complex ion with 4 coordinate bonds that nit tetrahedral ?

Answer 33

Square planar , 90*

Question 34

When do square planar complexes occur , give an example

Answer 34

Transition metals ions with eight electrons in highest energy d sub shell so pd,Pt, Au Eg [Pt(NH3)4]^2+

Question 35

What colour is [Cu(H20)6]^2+

Answer 35

Pale blue

Question 36

What does Cu^2+(aq) + NH3 make?

Answer 36

Cu(OH)2(s) | Pale blue to pale blue ppt

Question 37

What happens when Cu^2+ is reduced by I- ions?

Answer 37

White ppt of CuI | Brown I2

Question 38

What happens in disproportionation of Cu^+

Answer 38

Brown Cu solid and blue soloution of CuSO4

Question 39

What colour is [Cr(H20)6]^3+

Answer 39

Violet

Question 40

What happens when Cr^3+ aqueous reacts w NH3

Answer 40

Cr(OH)3(s) | Violet to Grey green ppt

Question 41

What happens when Cr^3+ reacts w hot H2O2

Answer 41

Forms CrO4^2- | Yellow

Question 42

What colour is [Mn(H2O)6]^2+

Answer 42

Pale pink

Question 43

What colour is [Fe(H20)6]^2+

Answer 43

Pale green

Question 44

What’s the colour change when MnO4^2- goes to Mn^2+

Answer 44

Purple to pale pink but so dilute it’s colourless

Question 45

What happens when I-/Fe^3+ goes to I2/Fe^2+

Answer 45

Orange brown to brown

Question 46

What colour is [Fe(H20)6]^3+

Answer 46

Yellow