Chapter 5, Problem 70A

Interpretation Introduction

Interpretation : The spectrum is continuous except for a dark line at 589 nm is to be observed and explained.

Concept Introduction : The study of atoms (and atomic ions) through their interactions with electromagnetic radiation is known as atomic spectroscopy. The atomic emission spectrum consists of a limited number of narrow lines of light whose wavelength is characteristic of the element.

Answer to Problem 70A

The spectrum is continuous except for a dark line because the electron is not capable of releasing a photon at 589 nm.

Explanation of Solution

The electrons in atoms migrate to higher energy levels when they absorb energy. When these electrons fall in energy, they lose energy by releasing light.

But at 589 nm, the spectrum is continuous and a dark line is observed.

The sodium atom's outermost electron absorbs photons with a wavelength of 589 nm when it moves to a higher energy level, but it lacks the energy to release a photon with this wavelength.