5: Properties of Transition Metals and Ligands

Question 1

What is the definition of a transition metal?

Answer 1

Metals that can form one or more stable ions with an incomplete D sub shell.

Question 2

Which 2 elements do not count as transition elements?

Answer 2

Scandium and Zinc

Question 3

Why are scandium and zinc not considered transition metals?

Answer 3

They do not form ions with incomplete d subshells.

Question 4

Give the shortened electron configuration of chromium.

Answer 4

[Ar] 4s1, 3d5

Question 5

Give the shortened electron configuration of copper.

Answer 5

[Ar] 4s1 3d10

Question 6

For copper and chromium, why does the 4s subshell not fill fully?

Answer 6

The atom is more stable when the 3d subshell is either full or half full.

Question 7

Give the shortened electron configuration of Cu2+

Answer 7

[Ar] 3d9

Question 8

Give 2 physical properties of transition metals.

Answer 8

High density
High melting/boiling point

Question 9

What type of ions can transition elements form?

Answer 9

Complex

Question 10

What can transition metal ions do that normal metal ions can’t do?

Answer 10

They can form coloured ions.

Question 11

Why can transition metals form ions with different charges?

Answer 11

They have variable oxidation states

Question 12

What is a complex ion?

Answer 12

An ion formed when a transition metal is surrounded by ligands that bond to it by donating lone pairs into vacant d orbitals

Question 13

Ligands always form which type of bonds?

Answer 13

Coordinate bonds

Question 14

What are ligands?

Answer 14

Atoms or ions that have a lone pair to form a coordinate bond with other metals.

Question 15

What is the coordination number?

Answer 15

The number of coordinate bonds formed by ligands to metal ions.

Question 16

What is a unidentate ligand?
Give some examples.

Answer 16

Ligands that form one coordinate bond.
NH3, :Cl-, :CN-

Question 17

In Ag+ complexes, what shape will the ion be?
What will the bond angle be?
What will the coordination number be?

Answer 17

Linear
180 degrees
Coordination number 2

Question 18

In large ligands (eg: :Cl-), what shape will the ion be?
What will the bond angle be?
What will the coordination number be?

Answer 18

Tetrahedral
Bond angle 109.5
Coordination number 4

Question 19

In Pt2+ complexes, what shape will the ion be?
What will the bond angle be?
What will the coordination number be?

Answer 19

Square planar
90 degrees bond angle
Coordination number 4, 2 lone pairs

Question 20

In most complex ions, what shape will the ion be?
What will the bond angle be?
What will the coordination number be?

Answer 20

Octahedral
Bond angle 90
Coordination number 6

Question 21

What are bidentate ligands?

Answer 21

Ligands that form 2 coordinate bonds

Question 22

Give 2 examples of bidentate ligands.

Answer 22

En, (C2O4 2-)

Question 23

What is another name for complex ions that form a multidentate ligand?

Answer 23

Chelate

Question 24

Chelates can be used to remove d block metal ions from what?

Answer 24

Remove them from solution

Question 25

Name the element that creates a ligand in haem groups.
This atom froms the complex called g_____

Answer 25

Nitrogen. Forms part of the globin complex.

Question 26

Why is the binding of oxygen to haemoglobin reversible?

Answer 26

The bond between the iron ion and oxygen is weak, so oxygen easily be unloaded where needed.

Question 27

Why is the binding of CO to haemoglobin irreversible?

Answer 27

CO is a ‘better ligand’.

Question 28

Describe how optical isomerism works in ligands with different atoms.

Answer 28

Ligands will be on different atoms.

Question 29

Finish the substitution reaction equation for
[Co(H2O)6]2+ + 6NH3

Answer 29

[Co(H2O)6]2+ + 6NH3 -> [Co(NH3)6]2+ + 6H2O

Question 30

Finish the substitution reaction equation for [Cu(H2O)6]2+ + 4Cl-

Answer 30

[Cu(H2O)6]2+ + 4Cl- -> [CuCl4]2- + 6H2O

Question 31

Finish the substitution reaction equation for [Cu(H2O)6]2+ + 4NH3

Answer 31

[Cu(H2O)6]2+ + 4NH3 -> [Cu(H2O)2(NH3)4]2+ + 4H2O

Question 32

Why is the reaction with CN- ligands irreversible?

Answer 32

It forms strong bonds

Question 33

What type of isomerism can complex ions with a square planar shape and octahedral shape show?

Answer 33

E/Z

Question 34

Describe arrangement of ligands in a cis isomer of an octahedral complex ion.

Answer 34

If the 2 different ligands to the other 4 are next to each other, it is cis.

Question 35

Describe arrangement of ligands in a trans isomer of an octahedral complex ion.

Answer 35

If the 2 ligands that are different to the other 4 are opposite each other, it is trans.

Question 36

Finish the ligand substitution equation for this reaction:
[Fe(H2O)6]3+ + 6CN-

Answer 36

[Fe(H2O)6]3+ + 6CN- -> [Fe(CN)6]3- + 6H2O

Question 37

For most substitution reactions, is enthalpy likely to be positive or negative?

Answer 37

Negative

Question 38

Finish the substitution equation for this reaction.
[Cu(H2O)6]2+ + 3en

Answer 38

[Cu(H2O)6]2+ + 3en -> [Cu(en)3] + 6H2O

Question 38

Explain why entropy increases for this reaction:
[Ni(NH3)6]2+ + 3en -> [Ni(en)3]2+ + 6NH3
State the feasibility of this reaction.

Answer 38

There are more molecules on the right than the left. This means the reaction will always be feasible.