Chapters 4 and 25: The Structure of the Atom & Nuclear Chemistry
LESSON ESSENTIAL QUESTIONS
1) How do the atomic models of Aristotle, Democritus and Dalton compare?
2) What are the main points of the atomic theory models developed by:
Aristotle, Democritus, Lavoisier, Dalton, Thomson, Millikan, Rutherford,
and Chadwick?
3) What is the law of definite proportions?...the law of multiple proportions?
4) What was Dalton's atomic theory?
5) What are the parts of a cathode ray tube?
6) How do subatomic particles compare in terms of relative charge and mass?
7) What are the charges of and symbols for the electron, proton, and neutron?
8) How can the atomic number and mass number be used to find the number of protons, neutrons, and
electrons in an atom?
9) How is average atomic mass calculated for an element?
10) How do alpha, beta and gamma radiation compare?
Bohr,
VOCABULARY: atom, anode, cathode, cathode rays, electron, proton, neutron, subatomic particle, atomic
number, mass, number, nucleons, nuclide, mass spectrometer, isotope, radioactivity, radiation (turn in on test
day)
http://education.jlab.org/atomtour/
Jefferson labs atom tour
CHAPTER 4 - ATOMIC STRUCTURE
Model: A __________ idea used to explain __________ facts __________ in__________.
Theory: An __________ of __________ facts and __________.
To remain valid, models and theories must:
- __________ all known __________
- enable __________ to make correct __________
Democritus (400 B.C.):
- proposed the __________ of an __________
- word comes from the __________ word __________ which means__________ __________ __________ or
“indivisible”
Aristotle
-__________ the __________ of the __________
- said __________ could be __________ __________
Dalton’s theory proposed that atoms:
-are __________ __________ of __________
-are __________
-of the __________ __________ are __________
-of __________ __________ are __________
-__________ in __________, __________ __________ ratios to form__________
J.J. Thomson (1896)
- credited with __________ of __________:
- a blow to __________ __________ atom
- proposed the __________ __________ model of the __________:
- __________ charged __________ embedded in a ball of __________ __________
Rutherford’s Gold-foil Experiment: (1909-Planetary Model)
-aimed __________ __________ at __________ __________
-__________ passed __________
- __________ particles were __________
-__________ particles even __________ __________
Conclusions of Rutherford's experiment:
-__________ of the __________ is __________ __________
-__________ ____________ charged __________
The Chemistry Quiz CR1._____ CR2._____ 1._____ 2._____3._____
4._____5._____
The only change in Dalton's theory today is to change the word mass to "average mass".
Dalton also developed the law of________________________ which states that the ratio of masses of one element that
combine with a constant amount of another element can be expressed in small whole numbers.
Cathode Ray Tube http://www.dlt.ncssm.edu/core/c3.htm
The positive terminal is called an ________. Its negative terminal is called a _______________. The rays that appeared
in the tube were called ______________ ________________.
__________________ used the cathode ray tube to discover the electron. He calculated the_________ to _______ ratio
of the electron. The sign of the charge on an electron is _____________. The symbol ________ is used for an
electron.
http://micro.magnet.fsu.edu/electromag/java/rutherford/ Gold foil experiment
Discovery of x-rays video
http://chemed.chem.purdue.edu/demos/main_pages/6.1.html Crooke’s tube
http://www.chem.uiuc.edu/clcwebsite/cathode.html Cathode ray tube (J.J. Thomson)
Oil Drop Experiment
_____________________ determined the charge on the electron with his _____________ experiment.
http://www.bun.falkenberg.se/gymnasium/amnen/fysik/millikaneng.html Oil drop simulation
http://cwx.prenhall.com/bookbind/pubbooks/petrucci8/medialib/media_portfolio/02.html
The positive ____________ was also discovered using a cathode ray tube.
The proton is ________ x the mass of the electron.
Isotopes
_______________ also discovered isotopes. Isotopes are atoms of the same element with the same number of
_____________ but a different number of ___________.
___________ determined the number of protons in many elements by using the wavelength of the X-ray produced by a
particular metal anode of the X ray tube.
The number of __________ determines the identity of an element.
___________ is a particular kind of atom containing a definite number of protons and
neutrons.
Note Taking Guide: Episode 302
Nucleons- __________ in the __________ of __________
-__________
-__________
Atomic Number- __________ of __________ in the __________ of an__________
Neutral atom- # of __________ (+) = # of __________ (-)
Isotope- __________ of an __________ that have __________
__________of __________.
Isotopes of Hydrogen
Isotope
Protons
Hydrogen-1
Protium
Hydrogen-2
Deuterium
Hydrogen-3
Tritium
Neutrons
Abundance
5 999/6000
Symbol
1/6000
Found in lab only
Mass Number- __________ number of __________ and __________ in an__________.
Example: Carbon-14 _________________ Neon-20 _________________
Subatomic particle
charge
mass
location
electron
proton
neutron
(1932)
Atomic Mass- __________ of the __________ of all the element’s __________
discoverer
Subatomic Particles
# of protons =__________ __________
# of electrons(in neutral atom) = __________ __________
# of neutrons = __________ __________ - __________ __________
iron:
oxygen-17
26
__________ protons
__________ protons
8
__________ electrons
Fe
__________ electrons
O
__________ neutrons
__________ neutrons
55.8
15.9
9
__________ protons
__________ electrons
__________ neutrons
The Chemistry Quiz
Nuclide
CR1._____ CR2._____ 1._____ 2._____3._____ 4._____ 5._____
Protons
Neutrons
Mass number
Atomic number
electrons
carbon-14
5 Li
3
5 Li2+
3
The atomic number – charge = # eAVERAGE ATOMIC MASS
A _________________________ is an instrument used to measure the masses and amounts of the nuclide of elements.
The ________________ is the average atomic mass of all the nuclide of an element as they occur in ________.
To find the average atomic mass find the sum of the percent times the mass of each nuclide and divide by 100.
Example : Neon-20 has a mass of 19.992 u and neon-22 has a mass of 21.991 u. In a sample 90% is neon-20 and 10%
is neon-22. Find the atomic mass of neon.
(______ % x mass of neon-20 ) + ( ____% x mass of neon-22 )
(% x mass of neon-20)+(% x mass of neon-21) = (90 x 19.992 u)+(10 x 21.991 u) = 20.192 u
100
100
Or (0.90 x 19.992 u)+(0.10 x 21.991 u) = 20.192 u
Note: 6% = 0.06
1% = 0.01
10% = 0.10
RADIOACTIVITY
Note Taking Guide - Program 1501
Nucleons:
- are particles occupying the ______________
- consist of __ charged ___________ and ____________ _____________
- have almost 2000times the _________ of ________________
- are made up of ____________ and ____________
27
Nuclear Notation:
atomic ________ ( )
Al
= ________+ _________
13
atomic _________ ( )
= no. of ________ (= _________ )
27
13 Al has _____ protons and ______ neutrons, for a total of _______ nucleons.
28
13
Al has _____ protons and ______ neutrons, for a total of _______ nucleons.
Isotopes: atoms of _________ element with different numbers of__________ (different _________ )
Forces Acting on Nucleons:
Strong forces –
-forces of _____________ between nucleons
-are independent of the __________ of the nucleon
-are short range (exist only between ____________ neighbors)
Electrical force –
-force of ____________ between _____ charged protons
-are _________ range
When are nuclei unstable?
a. large nuclei (Z > 82) - electrical forces of ____________ are greater than strong
____________
b. wrong neutron : proton _________
A radioactive isotope:
-has an _____________ nucleus
-spontaneously emits a __________ and ________ into another _________
transmutation – changing into another __________ through
radioactive________________
_____________ discovered radiation. _____________ AND _____________
_____________ discovered the radioactive elements Plutonium and Radium.
forces of
Types of Radioactive Emission:
Property
Symbol
Composition
Stopped
by
Charge
Mass
Electrical field
Alpha
Beta
Gamma
Nuclear Equations:
alpha decay: 21484 Po42He + _______
beta decay:
209
82
Pb  0-1e-
+ _______
During beta decay, a neutron changes into a proton and an _________.
1 n  1 p
+ _______
0
1
half-life:
-the _________ it takes for ________ the ________ of a radioactive
to ____________
-ranges from a fraction of a __________ to billions of ___________
-is _______ affected by _____________ conditions
sample
http://www.darvill.clara.net/nucrad/hlife.htm
half-life
http://www.sciencecourseware.com/VirtualDating/files/RC0/RC_0.html
carbon dating
________________ reactions involve a change in the atoms nucleus.
__________________ is the spontaneous emission of energy rays from unstable
atomic nuclei. The rays and particles emitted by the radioactive material are called _____________________.
NUCLEAR STRUCTURE
Protons and neutrons are made up of three smaller particles called _________ .
An ____________ is a mirror-image particle that exists for every particle.
There are 6 kinds of quarks ______, ______, ______, ______, ______, & _______.
Each comes in three _________ or ________, _____, ______, or ________.
When an atom loses an alpha particle the atomic number goes down by______ and
mass number goes down by ______.
Carbon-14 undergoes beta radiation. the reaction is 146C  147 N + ___________
When an atom loses an beta particle the atomic number does up by ____ and the
mass number goes ________ ______________.
the
Gamma radiation does not affect the atomic # or mass #.
http://www.wwnorton.com/college/chemistry/gilbert/tutorials/ch2.htm
balancing nuclear reactions
Note Taking Guide - Program 1502
TYPES OF NUCLEAR REACTIONS
238 U  234 Th + 4 He
_________________ transmutation - Uranium spontaneously decays.
92
90
2
_________________ transmutation - bombardment of a stable isotope to force it to decay.
14 N + 4 He 1 p
+ _______
7
2
1
Nuclear bullet
When the bullets are ___ charged, they are ____________ by the nucleus they are
bombarding. To overcome the repulsions, they must be _______________ to very
speeds by ______________ accelerators.
nuclear fission - Heavy nuclei are bombarded with neutrons and split.
1 n + 235 U 142 Ba
+ 9136 Kr + 3(______) + E
0
92
56
Mass of particles produced is slightly ______ than the mass of the reactants.
This mass is converted into ___________. (E =
)
Critical mass: ____________ mass of _______________ material required for a
___________ ____________
nuclear reactors: control fission ___________ reactions to produce energy
dangers:
nuclear fusion - combination of _____ nuclei into ____ with release of _____
2 H
+ 31H  42 He + 10n + E
1
Deuterium tritium
helium
Mass of particles produced is much ______ than the mass of the __________.
This _______ is converted into energy. (E =
)
high