Chapter 22, Problem 32QP

Interpretation Introduction

Interpretation:

The complex from the given complex pairs that absorb light at a longer wavelength is to be identified.

Concept Introduction:

When a photon or light strikes an atom/ion/compound, its absorption will take place if the energy of the photon is ${\text{ΔE=E}}_{\text{Ground state}}{\text{- E}}_{\text{Excited state}}$. This is because an electron of the atom or ion is promoted to a higher-energy level orbital. The lower energy corresponds to a smaller crystal field splitting.

The wavelength of a photon is inversely proportional to its energy, $\text{E}$. The weaker ligands absorb light at longer wavelengths, while the stronger ligands absorb it at smaller wavelengths.

Spectroscopy gives a clear method to measure the magnitude of the crystal field splitting by determining the wavelength at which the light is absorbed.