Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
Solving Problems: A Chemistry Handbook
Chemistry: Matter and Change
41
Electrons in Atoms
Electrons in Atoms
SOLVING PROBLEMS:
A CHEMISTRY HANDBOOK
CHAPTER
5
5.1 Light and Quantized Energy
In the early twentieth century, scientists accepted the idea that an
atom consisted of a massive, positively charged nucleus surrounded
by negatively charged electrons. Further explanation of the atom’s
electron arrangement came from research involving light and its
interaction with matter.
Wave nature of light Visible light is part of a range of electromagnetic radiation, a form of wave energy that travels through
empty space and is propagated in the form of alternating electric and
magnetic fields. X rays, gamma rays, and radio waves are other
examples of electromagnetic radiation.
Electromagnetic waves, along with water waves and sound
waves, exhibit certain common characteristics. All waves consist of
a series of crests and troughs that travel away from their source at a
velocity that is determined by the nature of the wave and the material through which the wave passes. The rate of vibration of a wave
is called its frequency and is defined as the number of waves that
pass a given point per second. Wave frequency is expressed in hertz
(Hz); one hertz equals one wave per second (s Ϫ1 ).
The frequency and velocity of a wave determine its wavelength,
the distance between equivalent points on a continuous wave. For
waves of a given velocity, a wave with a higher frequency has a
shorter wavelength. For electromagnetic waves, this inverse relation
is expressed mathematically by the following equation.
c ϭ
In this equation, c equals 3.00 ϫ 10 8 m/s, the velocity of electromagnetic waves in a vacuum; equals the wavelength in meters;
and is the frequency of the waves in hertz.
Practice Problems
1. A helium-neon laser emits light with a wavelength of 633 nm.
What is the frequency of this light?
▲
Solving Problems: A Chemistry Handbook
Chemistry: Matter and Change
41
Electrons in Atoms
Electrons in Atoms
SOLVING PROBLEMS:
A CHEMISTRY HANDBOOK
CHAPTER
5
5.1 Light and Quantized Energy
In the early twentieth century, scientists accepted the idea that an
atom consisted of a massive, positively charged nucleus surrounded
by negatively charged electrons. Further explanation of the atom’s
electron arrangement came from research involving light and its
interaction with matter.
Wave nature of light Visible light is part of a range of electromagnetic radiation, a form of wave energy that travels through
empty space and is propagated in the form of alternating electric and
magnetic fields. X rays, gamma rays, and radio waves are other
examples of electromagnetic radiation.
Electromagnetic waves, along with water waves and sound
waves, exhibit certain common characteristics. All waves consist of
a series of crests and troughs that travel away from their source at a
velocity that is determined by the nature of the wave and the material through which the wave passes. The rate of vibration of a wave
is called its frequency and is defined as the number of waves that
pass a given point per second. Wave frequency is expressed in hertz
(Hz); one hertz equals one wave per second (s Ϫ1 ).
The frequency and velocity of a wave determine its wavelength,
the distance between equivalent points on a continuous wave. For
waves of a given velocity, a wave with a higher frequency has a
shorter wavelength. For electromagnetic waves, this inverse relation
is expressed mathematically by the following equation.
c ϭ
In this equation, c equals 3.00 ϫ 10 8 m/s, the velocity of electromagnetic waves in a vacuum; equals the wavelength in meters;
and is the frequency of the waves in hertz.
Practice Problems
1. A helium-neon laser emits light with a wavelength of 633 nm.
What is the frequency of this light?
▲