Chromophores and Absorption of Light Quiz

DeftPluto avatar

Start Quiz

Study Flashcards

12 Questions

Which of the following compounds is an example of a compound with sufficient conjugation that absorbs in the visible region?


What effect does the length of the conjugated system generally have on the values of λmax?

It increases the values of λmax

What is an auxochrome?

A group that increases the value of λmax by extending the conjugation through resonance

Which of the following is NOT an example of an auxochrome group?


What is the general effect of bathochromic groups on wavelength?

They cause a red shift

What does ΔE = hν= hc/λ represent?

The relationship between energy, frequency, and wavelength

What type of transitions do chromophores with both π and non-bonding electrons undergo?

π → π* and n → π* transitions

What is the role of chromophores in relation to the color of compounds?

They increase the ability to absorb radiation

What happens to the absorption maximum when two or more conjugated chromophore groups are present?

It is shifted to a longer wavelength

Which compound shows a lower energy transition, 1,3-butadiene or ethylene?


What type of molecular orbitals are formed in conjugated dienes, from the separate alkene groups?

2 bonding molecular orbitals and 2 antibonding molecular orbitals

Which compound shows a higher absorption maximum, ethylene or 1,3-butadiene?


Study Notes

Conjugation and Absorption

  • Compounds with sufficient conjugation absorb in the visible region.
  • The length of the conjugated system generally increases the values of λmax.

Auxochrome Groups

  • An auxochrome is a group that increases the intensity of color by extending the conjugation of a chromophore.
  • The -OH group is not an example of an auxochrome group.

Bathochromic Groups

  • Bathochromic groups shift the absorption maximum to a longer wavelength.

Energy Transitions

  • ΔE = hν = hc/λ represents the energy of a transition.

Chromophores and Transitions

  • Chromophores with both π and non-bonding electrons undergo n → π* and π → π* transitions.
  • The role of chromophores is to determine the color of compounds by absorbing specific wavelengths of light.

Multiple Chromophore Groups

  • When two or more conjugated chromophore groups are present, the absorption maximum increases.

Comparing Compounds

  • 1,3-butadiene shows a lower energy transition than ethylene.
  • 1,3-butadiene shows a higher absorption maximum than ethylene.

Molecular Orbitals

  • In conjugated dienes, separate alkene groups form molecular orbitals that are delocalized and extended.

Test your knowledge on chromophores and their role in the absorption of light. Explore the factors affecting the wavelength and intensity of absorption in compounds containing chromophores.

Make Your Own Quizzes and Flashcards

Convert your notes into interactive study material.

Get started for free

More Quizzes Like This

Use Quizgecko on...