TOPIC 15: Transition Metals

Question 1

What is a Transition Metal ?

Answer 1

A Transition metal is a d-block metal that forms one or more stable ions with incompletely filled d- orbitals.

Question 2

What are some Characteristics of Transition Metals ?

Answer 2

1. Can exist in various oxidation states
2. Can form Coloured ions in solution
3. Can form Complex Ions
4. Catalytic activity

Question 3

Why are Chromium and Copper exceptions to the standard electron configuration rules?

Answer 3

The 3d5 and 3d10 subshells are more energetically favourable than 3d4 4s2 for chromium and 3d9 4s2 for copper.

Question 4

What is special about zinc and Scandium and why?

Answer 4

Zinc can only form a 2+ ion, this ion has a complete d orbital so does not fill the criteria of having an incomplete d orbital . Scandium can only form a 3+ ion, this ion has an empty d orbital so does not meet the criteria of having an incomplete d orbital.

Question 5

Define Ligand

Answer 5

An atom, ion or molecule which can donate a lone electron pair and forms a dative covalent bond to a central atom/ion.

Question 6

Define Complex

Answer 6

Central metal ion surrounded by Ligands. The positive metal ion is stabilized by the Ligands and ion can make as many bonds as can fit usually up to 6.

Question 7

Define Co-ordination Number

Answer 7

The number of co-ordinate bonds formed to a central metal ion.

Question 8

What is the maximum oxidation state for a transition metal ?

Answer 8

It is the number of 4s electrons plus the number of unpaired 3d electrons.

Question 9

Define monodentate

Answer 9

Has one lone pair of electrons and can form only one dative covalent bond with the central metal ion.

Question 10

Define Bidendate

Answer 10

Has two lone pair of electrons and can form two dative covalent bonds with the central metal ion

Question 11

Why is H20 classified as monodentate rather than bidentate?

Answer 11

H20 is a very small molecule and its lone pairs are very close together so it can only form one dative covalent bond at a time.

Question 12

Define Multidentate Ligands

Answer 12

Form three or more dative covalent bonds with the central metal ion.

Question 13

What are the common shapes of ion in transition metals?

Answer 13

1. Octahedral
2. Tetrahedral
3. Square planar
4. Linear

Question 14

What elements are exceptions to the shape complexes in transition metals?

Answer 14

1. Platinum and Silver

Platinum: Platinum has a co-ordination number of 4 and it would be expected to form a tetrahedral shape however it has a square planar shape and this could experience isomerism.

Silver: Silver forms (CHECK THIS)