Chapter 24 - Transition elements

Question 1

What is a transition element?

Answer 1

D-block elements that form an ion with an incomplete d-subshell

Question 2

What are unique properties of transition elements?

Answer 2

• Form coloured ions
• Have multiple oxidation states
• Can be used as catalysts

Question 3

An example of transition elements used as catalysts:

Answer 3

• 2H2O2 –(MnO2)–> 2H2O +O2

Question 4

Define ligand

Answer 4

A molecule or ion which can donate a pair of electrons to the central transition metal ion

Question 5

Define coordination number

Answer 5

The number of dative covalent bonds formed between ligands and a central metal ion

Question 6

Name 3 monodentate ligands

Answer 6

• Cl-
• H2O
• NH3

Question 7

Name a hexadentate ligand

Answer 7

EDTA

Question 8

Which elements form square planar structures and what is it’s bond angle?

Answer 8

Pt and Ni
90 degrees

Question 9

Give an example of a square planar structure

Answer 9

Cis/trans-platin

Question 10

What type of isomerism do octahedral structures show?

Answer 10

• Cis/trans if monodentate ligands
• Optical if bidentate ligands

Question 11

What are optical isomers?

Answer 11

Compounds that have the same structural formulae but are mirror images of one another

Question 12

Why is cis-platin affective as an anti-cancer drug?

Answer 12

• Cis-platin targets parts of cells which are chiral, so only one orientation of the isomer is affective
• It binds to DNA and prevents cell division

Question 13

Colour change of:
[Cu(H2O)6]2+ + 4Cl-

Answer 13

Pale blue to yellow

Question 14

Colour change of:
[Cu(H2O)6]2+ + 4NH3

Answer 14

Pale blue to dark blue

Question 15

Colour change of:
[Cr(H2O)6]3+ + 6NH3

Answer 15

Pale purple to purple

Question 16

Colour change from Fe2+ to Fe3+

Answer 16

Brown to orange

Question 17

Colour change from Cr3+ to (Cr2O7)2–

Answer 17

Green to orange