Topic 17: Transition metals

Question 1

What is a transition metal?

Answer 1

• an element that forms one or more stable ions with incompletely filled d-orbitals

Question 2

What two elements do not fit the definition of a transition metal?

Answer 2

• Scandium
  forms Sc 3+ ion;
  [Ar] 3d 0
• Zinc
  forms Zn 2+ ion;
  [Ar] 3d 10

Question 3

Which two metals do not fit the expected pattern for spdf notation?

Answer 3

• Copper
• Chromium
• Both have a partially filled 4s orbital (4s¹)
• normally metals will fill up their 4s orbitals before 3d orbitals

Question 4

What is a ligand?

Answer 4

• a species that uses a lone pair of electrons to form a dative covalent bond with a metal ion
• similar to a nucleophile

Question 5

What is a dative (coordinate) bond?

Answer 5

• bond formed between central metal atom and ligand
• both bonding electrons supplied by ligand

Question 6

What is a complex?

Answer 6

• a species containing a metal joined to a ligand

Question 7

What is a complex ion?

Answer 7

• a species containing a metal ion joined to ligands with an overall positive or negative charge

Question 8

What is the coordination number?

Answer 8

• number of dative bonds in the complex

Question 9

Give some examples of monodentate ligands:

Answer 9

1. Water
   - H2O
   - 0
   - Aqua
2. Hydroxide
   - OH-
   - -1
   - Hydroxo
3. Ammonia
   - NH3
   - 0
   - Ammine
4. Chloride
   - Cl-
   - -1
   - Chloro
5. Cyanide
   - CN-
   - -1
   - Cyano

Question 10

How are complexes named?

Answer 10

1. number of ligands (hexa, tetra)
2. name of ligand; ligands with a negative charge end in -o (cyano, chloro)
3. name of metal ion (negatively charged complex ion means metal will use latin name)
4. oxidation number of metal ion

Question 11

How are complexes represented?

Answer 11

• Square brackets are used to group together the ligands and metal ion in a representation of the geometrical arrangement
• The overall charge on the complex ion is the sum of the oxidation states of all the species present
• If the ligands are neutral then the overall charge will be the same as the oxidation state of the metal ion