UV-Visible Light Absorption and Transitions
5 Questions
1 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to Lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

Which electronic transition requires the highest amount of energy?

  • π to π* transition
  • σ to σ* transition (correct)
  • n to π* transition
  • n to σ* transition

Which of the following compounds is likely to undergo an n to σ* transition?

  • Propyne
  • Ethene
  • Ethanol (correct)
  • Methane

In which type of transition is less energy required than for the π to π* transition?

  • σ to σ* transition
  • n to π* transition (correct)
  • n to σ* transition
  • π to π* transition

Which of the following correctly describes a π to π* transition?

<p>Occurs in unsaturated and aromatic compounds (B)</p> Signup and view all the answers

Which compounds are likely to undergo n to π* transitions?

<p>Alcohols and ethers (D)</p> Signup and view all the answers

Flashcards

σ to σ* transition

An electronic transition where an electron moves from a sigma bonding orbital to a sigma antibonding orbital. This requires a high energy input.

n to σ* transition

An electronic transition where an electron moves from a non-bonding orbital (lone pair) to a sigma antibonding orbital. This requires a moderate amount of energy.

n to π* transition

An electronic transition where an electron moves from a non-bonding orbital (lone pair) to a pi antibonding orbital. This requires less energy than σ to σ* transitions.

π to π* transition

An electronic transition where an electron moves from a pi bonding orbital to a pi antibonding orbital. This requires more energy than n to π* transitions.

Signup and view all the flashcards

UV-Vis Spectroscopy

The energy required for an electronic transition corresponds to the energy of a photon of light that can be absorbed by the molecule. Different types of transitions occur at different wavelengths of light.

Signup and view all the flashcards

Study Notes

UV-Visible Light Absorption and Electronic Transitions

  • Four types of electronic transitions can occur when a molecule absorbs UV-Visible light.

σ to σ* Transition

  • Requires a high energy input.
  • Found in saturated hydrocarbons (e.g., methane, propane).

n to σ* Transition

  • Involves molecules with lone pairs of electrons.
  • Examples include alcohols, ethers, aldehydes, and ketones.

n to π* Transition

  • Requires less energy than σ to σ* transition.
  • Occurs in molecules with double or triple bonds.
  • Examples include saturated aldehydes.

π to π* Transition

  • Happens in unsaturated molecules and aromatic compounds.
  • Needs slightly more energy than n to π* transition.
  • Examples include ethene, ethyne, alkenes, alkynes.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Quiz Team

Description

Explore the four types of electronic transitions that occur during UV-Visible light absorption in molecules. This quiz covers σ to σ*, n to σ*, n to π*, and π to π* transitions, highlighting the energy requirements and examples of each type. Test your understanding of how these transitions apply to various organic compounds.

More Like This

Use Quizgecko on...
Browser
Browser