Developing Metals 3: Coloured ions

Question 1

Describe the energy in the five d orbitals of transition metals

Answer 1

In transition metal compounds the five d orbitals do not all have the same

Question 2

What do ligands surrounding a metal ion cause ( in terms of sub shell )

Answer 2

• ligands surrounding the metal ion cause the 5 d subshell to split into a 2 and 3
• = creating a gap in energy ( delta E ) between the orbitals ( 3 orbitals always lower than 2 )

( look at notes for clarification )

Question 3

What does the gap in energy between the d orbitals ( 2 and 3 ) correspond to

Answer 3

Energy of UV/ visible light

Question 4

What do electrons do to the gap in energy between the d orbitals

Answer 4

???????

Electrons absorbs UV/visible light to provide the energy to promote excited electrons to the higher energy level ?

Question 5

Describe what the colour seen of complexes is in terms of visible light and absorption

Answer 5

Colour you see is a mixture of the colours of visible light that are NOT absorbed

Question 6

Standard answer for explain why the ( iron / any ) compound is coloured ( 4 marks )

Answer 6

1. 3d subshell / energy levels split by ligands
2. Electrons move ( excited / promoted ) to higher energy level
3. Light absorbed & E=hv ( E is proportional to frequency of visible light )
4. Complementary colour transmitted ( i.e this is the colour you see )

Question 7

Explain in terms of frequencies why solutions are often coloured ( 2 marker )

Answer 7

1. ( electrons ??? ) absorb frequencies in parts of the visible spectrum
2. Transmit ( reflect not allowed ) complementary colour