Download Electrons in Atoms

Name ____________________________________________________________ Date __________________
Electrons in Atoms
Before You Read
Chapter 4
Review the structure of the atom by completing the following table.
Part of the Atom
Description
proton
a subatomic particle with a positive
charge found in the nucleus
nucleus
centrally located part of the atom that contains
protons and neutrons
electron
negatively charged subatomic part of
the atom
neutron
subatomic particle with no charge found in the
nucleus
__________
Draw a typical atom and label the structures.
Identify three facts about electrons.
Example: Electrons are a part of the structure of an atom.
Accept all reasonable responses. Possible answers include:
1. ______________________________________________________
Most of an atom consists of electrons.
The mass of an electron is extremely small.
2. ______________________________________________________
The negative charge of an electron balances the positive
3. ______________________________________________________
charge of the nucleus.
______________________________________________________
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Name ____________________________________________________________ Date __________________
Electrons in Atoms
Section 1 Light and Quantized Energy
Scan Section 1 of your text. Use the checklist below as a guide.
 Read all section titles.
 Read all boldfaced words.
 Read all tables and graphs.
 Look at all pictures and read the captions.
Write three facts you discovered about light.
Accept all reasonable responses.
1. _____________________________________________________
2. _____________________________________________________
3. _____________________________________________________
Use your text to define each term.
electromagnetic
radiation
a________________________________________________________
form of energy that exhibits wavelike behavior as it travels through space
wavelength
the
shortest distance between equivalent points on a continuous wave
________________________________________________________
frequency
the
number of waves that pass through a given point per second
________________________________________________________
amplitude
the
height of a wave from the origin to a crest or trough
________________________________________________________
electromagnetic
spectrum
all
forms of electromagnetic radiation
________________________________________________________
quantum
the
minimum amount of energy that can be gained or lost by an atom
________________________________________________________
Planck’s constant
value
used to determine the energy of a quantum
________________________________________________________
photoelectric effect
phenomenon
where electrons are emitted from a metal’s surface
________________________________________________________
when
light of a certain frequency shines on the surface
_______________________________________________________
photon
a________________________________________________________
particle of electromagnetic radiation with no mass that carries a quantum of energy
atomic emission
spectrum
set
of frequencies of electromagnetic waves emitted by atoms of an element
________________________________________________________
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Section 1 Light and Quantized Energy (continued)
The Atom and
Unanswered
Questions
List the three reasons scientists found Rutherford’s nuclear atomic model
to be fundamentally incomplete.
The model did not explain how the atom’s electrons are
1. ______________________________________________________
Use with pages 136.
arranged in the space around the nucleus.
______________________________________________________
It did not address the question of why the negatively charged
2. ______________________________________________________
electrons are not pulled into the atom’s positively charged nucleus.
______________________________________________________
It did not account for the differences in chemical behavior
3. ______________________________________________________
among the various elements.
______________________________________________________
Wave Nature
of Light
Explain the relationship shown by the figure below. Use the following
terms: wavelength, frequency, amplitude, and speed.
Use with pages 137–140.
There is an inverse relationship between wavelength and
______________________________________________________________
frequency.
frequency. As wavelength increases, frequency decreases. Speed
________________________________________________________
and
amplitude are not affected by wavelength and frequency.
________________________________________________________
________________________________________________________
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Name ____________________________________________________________ Date __________________
Section 1 Light and Quantized Energy (continued)
Calculating
Wavelength of an
EM Wave
Use with Example
Problem 1, page 140.
Solve Read Example Problem 1 in your text.
You Try It
Problem
Radio waves are used to transmit information on various channels. What is
the wavelength of a radio wave having the frequency of 5.401010 Hz?
1. Analyze the Problem
v = 5.40  1010 Hz and c = 3.00  108 m/s
Known:
__________________________________________
= ?m
UnKnown: __________________________________________
You know that because radio waves are part of the electromagnetic
spectrum, their speed, frequency, and wavelength are related by the
formula c  v.
2. Solve for the Problem
Solve the equation relating the speed, frequency, and wavelength of an
electromagnetic wave for wavelength ().
c/v
If c  v, then   ________
Substitute c and the frequency of the radio wave, v, into the equation.
Note that hertz is equivalent to 1/s or s1.

3.00  108 m/s
5.40  1010 s1
Divide the values to determine wavelength,  and cancel units as
required.

3.00  108 m/s
5.40  10
10
s
1
 0.555  102 m
3. Evaluate the Answer
wavelength (m)
The answer is correctly expressed in a unit of _______________.
3
Both of the known values in the problem are expressed with _______
3
significant figures, so the answer must have ___________
significant
figures.
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Science Notebook
Name ____________________________________________________________ Date __________________
Section 1 Light and Quantized Energy (continued)
Particle Nature of
Light
Identify two facts the wave model of light failed to explain.
Heated objects emit only certain frequencies of light at a
1. ______________________________________________________
Use with pages 141–143.
given temperature.
______________________________________________________
Some metals emit electrons when colored light of a specific
2. ______________________________________________________
frequency shines on them.
______________________________________________________
Describe Planck’s quantum concept by completing the following
statement.
energy only
The quantum concept concludes that matter can gain or lose _________
quanta
in small, specific amounts called ____________.
A quantum is the
gained or _________
lost
minimum amount of energy that can be __________
by an
atom.
Atomic Emission
Spectra
Use with pages 144–145.
Compare and contrast Einstein’s equation with Planck’s equation by
completing the following sentence.
Equantum  h
Planck’s equation, _____________,
demonstrates mathematically that the
frequency of the emitted radiation.
energy of a quantum is related to the ___________
Einstein went further by explaining that, in addition to its wavelike
characteristics, a beam of light can be thought of as a stream of
tiny particles called __________.
photons
____________
Contrast the continuous electromagnetic spectra and the atomic emission
spectra.
The electromagnetic spectrum is a continuous spectrum of
________________________________________________________
colors because there is no portion of it that does not correspond
________________________________________________________
to a unique wavelength and frequency of light. The atomic
________________________________________________________
emission spectrum, also known as a line spectrum, consists of
________________________________________________________
distinct colored lines of different frequencies.
________________________________________________________
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