[LostDepravity]

Hi Chemistry forum,

I would like to ask 3 questions which I hope to better my understanding on the topic.

1. Why does NH₃ undergo more electron repulsion than H₂O?

2. Suppose a complex ion undergoes a ligand exchange/substitution.
   e.g.
     [Cu(H₂O)₆]²⁺ + 4NH₃  [Cu(NH₃)₄(H₂O)₂]²⁺ + 4H₂O

I understand that the NH₃ would cause an increase in the energy gap. This would cause an increase in frequency, which would cause a decrease in wavelength. Would this wavelength be the wavelength of the color absorbed/reflected?

3. Why does the color change from pale blue to deep blue?

Many thanks on this!

[dayglo]

So first a couple questions:

1. So what happens if you draw a molecular orbital diagram of NH3 vs. H2O? What are some differences between N and O?

2&3. What's the difference between the deep blue and the pale blue? Is this indicative of the strength (i.e. molar extinction coefficient) of transition or the energy of the transition (has the wavelength changed)?