Transition Elements

Question 1

What is different about chromium and copper?

Answer 1

They fill d orbitals before s orbitals

Question 2

Why can transition metals form ions with different oxidation states?

Answer 2

Easy to lose 4s electrons and 3d electrons as the difference in energy is very small between the 4s and 3d orbitals.

Question 3

What oxidation state is most common at the start of the d block?

Answer 3

+3

Question 4

What oxidation state is most common at the end of the d block?

Answer 4

+2

Question 5

How can transition elements act as a homogeneous catalyst?

Answer 5

Variable oxidation states - Solution of metal can act as a catalyst in aqueous reactions.

Question 6

How can transition elements act as a heterogeneous catalyst?

Answer 6

Empty/available d orbitals at the correct energy level to accept electrons.

Question 7

What is the catalyst in the contact process?

Answer 7

V

Question 8

What is the catalyst in the Haber process?

Answer 8

Finely divided Fe

Question 9

What is the catalyst in the hydrogenation of alkenes?

Answer 9

Use Ni/Pt catalyst

Question 10

What is the catalyst in the decomposition of Hydrogen peroxide?

Answer 10

Co

Question 11

What is the definition of transition elements?

Answer 11

A d block element that forms at least one ion with an incomplete d sub-shell.

Question 12

What are the chemical properties of transition elements?

Answer 12

Form compounds with variable oxidation states
Form coloured compounds
Both elements and their compounds are good catalysts

Question 13

What are the physical properties of transition elements?

Answer 13

Dense
Durable
Ductile
Malleable
High boiling points
High tensile strength
High melting points

Question 14

Where are lower oxidation states normally found?

Answer 14

Simple ionic compounds

Question 15

Where are higher oxidation states normally found?

Answer 15

Molecular ions

Question 16

When are d block elements coloured in aqueous solution?

Answer 16

When they have a partially filled d orbital.

Question 17

What is the definition of a complex ion?

Answer 17

A transition metal ion bonded to one or more ligands by coordinate bonds.

Question 18

What is the definition of a ligand?

Answer 18

A molecule or ion that can donate a pair of electrons to the transition metal ion to form a coordinate bond

Question 19

What are examples of neutral monodentate ligands?

Answer 19

Water

Ammonia

Question 20

What are examples of charged monodentate ligands?

Answer 20

Hydroxide
Thiocyanate
Cyanide
Chloride

Question 21

What are monodentate ligands?

Answer 21

Ligands with one lone pair

Question 22

What are bidentate ligands?

Answer 22

Can donate 2 pairs of electrons to the central metal ion to form 2 coordinate bonds.

Question 23

What donates the lone pairs in Ethane - 1,2 - diamine

Answer 23

There are 2 N’s with lone pairs that they use to make 2 coordinate bonds.

Question 24

What is the example of a multidentate ligand?

Answer 24

EDTA

Question 25

What does the coordination number tell you?

Answer 25

How many coordinate bonds a transition metal can form

Question 26

What isomers can be formed by complex ions?

Answer 26

Cis - trans | Optical isomers

Question 27

What colour is copper 2+ (aq)?

Answer 27

Blue

Question 28

What happens to copper 2+ when NaOH is added?

Answer 28

Blue precipitate is formed

Question 29

What colour is Iron 2+ (aq)?

Answer 29

Green

Question 30

What happens to Iron 2+ when NaOH is added?

Answer 30

Green precipitate is formed

Question 31

What colour is Iron 3+ (aq)?

Answer 31

Purple

Question 32

What happens to Iron 3+ when NaOH is added?

Answer 32

Brown precipitate is formed

Question 33

What colour is Manganese 2+(aq)?

Answer 33

Pink

Question 34

What happens to manganese 2+ when NaOH is added?

Answer 34

Brown precipitate formed

Question 35

What colour is chromium 3+ (aq)?

Answer 35

Violet

Question 36

What happens to chromium 3+ when NaOH is added?

Answer 36

Green precipitate formed

Question 37

What happens to the green precipitate when excess NaOH is added to chromium 3+?

Answer 37

Precipitate dissolves

Question 38

What are the equations for reactions of transition metal ions with sodium hydroxide?

Answer 38

Mⁿ⁺(aq) + nOH⁻ (aq) -> M(OH)n (s)

Question 39

What is the stability constant K stab?

Answer 39

The equilibrium constant for an equilibrium existing between a transition metal ion surrounded by water ligands and the complex formed when the same ion has undergone a substitution reaction.

Question 40

What are the units of Kstab?

Answer 40

mol⁻ⁿdm^x

Question 41

What is the equation for the Kstab?

Answer 41

[product complex ion] / [reactant complex ion] X [Other reactant ligand]

Question 42

What happens as the value of Kstab gets larger?

Answer 42

The position of equilibrium lies further to the right. | The more stable the complex ion.

Question 43

What happens to copper 2+ when NH3 is added?

Answer 43

Blue precipitate

Question 44

What happens to Iron 2+ when NH3 is added?

Answer 44

Green precipitate

Question 45

What happens to Iron 3+ when NH3 is added?

Answer 45

Brown precipitate

Question 46

What happens to Manganese 2+ when NH3 is added?

Answer 46

Brown precipitate

Question 47

What happens to Chromium 3+ when NH3 is added?

Answer 47

Green precipitate

Question 48

What happens to Copper 2+ when excess NH3 is added?

Answer 48

Darker blue solution | Precipitate dissolves

Question 49

What happens to Iron 2+ when excess NH3 is added?

Answer 49

Precipitate doesn't dissolve

Question 50

What happens to Iron 3+ when excess NH3 is added?

Answer 50

Precipitate doesn't dissolve

Question 51

What happens to Manganese 2+ when excess NH3 is added?

Answer 51

Precipitate doesn't dissolve

Question 52

What happens to Chromium 3+ when excess NH3 is added?

Answer 52

Purple solution | Precipitate dissolves