Download Unit 1 Atomic Structure, Periodic Properties and Nuclear Chemistry

Unit 1 Atomic Structure, Periodic Properties and Nuclear Chemistry
 Chp 4 Atomic Structure Sec 1-2 Guided Reading Notes
 Chp 5 Electrons in Atoms Sec 1 (1st half) Guided Reading Notes
 Chp 4 Atomic Structure Sec 3 Guided Reading Notes
 Vocabulary
4.1 Defining the Atom
Early Models of the Atom
1. Democritus, who lived in Greece during the fourth century B.C., suggested that
matter is made up of tiny particles that cannot be divided. He called these particles
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2. List two reasons why the ideas of Democritus were not useful in a scientific sense.
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3. The modern process of discovery about atoms began with the theories of an English
schoolteacher named _____________________________________________________
4. Summarize the four postulates of Dalton’s Atomic Theory.
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Sizing up the Atom
5. Suppose you could grind a sample of the element copper into smaller and smaller
particles. The smallest particle that could no longer be divided, yet still has the
chemical properties of copper, is the _________________________________________
6. About how many atoms of copper when placed side by side would form a line 1 cm
long? __________________________________________________________________
4.2 Structure of the Nuclear Atom
Subatomic Particles
1. How is the atomic theory that is accepted today different from Dalton’s Atomic
Theory?
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2. Which subatomic particles carry a negative charge? __________________________
3. Thomson observed that the production of cathode rays did not depend on the kind
of gas in the tube or the type of metal used for the electrodes. What conclusion did he
draw from these observations?
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4. What two properties of an electron did Robert Millikan determine from his
experiments?
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5. What charge does a neutron carry? _______________________________________
6. What is the positively charged subatomic particle called? ______________________
7. What is the unit charge that remains when a hydrogen atom loses an electron?
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8. Complete the table.
Particle
Symbol
Relative
Relative Mass
Electrical
(mass of proton = 1)
Charge
Electron
Proton
Neutron
The Atomic Nucleus
10. An alpha particle has a double positive charge because it has lost two of which
subatomic particle? _______________________________________________________
11. Explain why in 1911 Rutherford and his coworkers were surprised when they shot a
narrow beam of alpha particles through a thin sheet of gold foil.
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12. Based on Rutherford’s experimental results, what three nuclear theories of the
atom can be suggested.
1. __________________________________________________________
2. __________________________________________________________
3. __________________________________________________________
5.1 Models of the Atom
The Development of Atomic Models
1. Complete the table describing the atomic models and the scientists who developed
them.
Scientist
Model of Atom
Dalton
Thomson
Rutherford
Bohr
Can electrons in an atom exist between energy levels? __________________________
The Bohr Model
3. What are the fixed energies of electrons called? _____________________________
4. A quantum of energy is the amount of energy required to
_______________________________________________________________________
5. In general, the higher the electron is on the energy ladder, the __________ it is
from the nucleus.
4.3 Distinguishing Among Atoms
Atomic Number
1. Complete the table.
Name
Symbol
Atomic #
# of
Protons
# of
Electrons
Hydrogen
Helium
Lithium
Boron
Carbon
Oxygen
Mass Number
2. The total number of protons and neutrons in an atom is its ____________________
3. What is the mass number of a helium atom that has two protons and two neutrons?
_______________________________________________________________________
4. How many neutrons does a beryllium atom have with four protons and a mass
number of nine? _________________________________________________________
5. Use the shorthand notation to symbolize neon-22. ___________________________
6. How many protons, neutron, and electrons does neon-22 possess?
_______________________________________________________________________
Isotopes
7. How do atoms of neon-20 and neon-22 differ?
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8. Neon-20 and neon-22 are called __________________________________________
Atomic Mass
9. Why is the atomic mass unit (amu), rather than the gram, usually used to express
atomic mass?
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10. What isotope of carbon has been chosen as the reference isotope for atomic mass
units? What is the defined atomic mass in amu of this isotope?
_______________________________________________________________________
11. Why is the atomic mass of an element not a whole number?
_______________________________________________________________________
12. What is the relationship between the weighted atomic mass of an element and the
relative abundance of its isotopes?
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13. When chlorine occurs in nature, there are three atoms of chlorine-35 for every one
of chlorine-37. Which atomic mass number is closer to the weighted atomic mass of
chlorine? 35 amu or 37 amu
Vocabulary
Define the following words and concepts
atom
Democritus’ atomic philosophy
Aristotle atomic philosophy
Dalton’s atomic theory
JJ Thomson’s atomic theory
electrons
cathode ray
RA Millikan’s atomic theory
Oil drop experiment
J Chadwick’s atomic theory
neutrons
E Rutherford’s atomic theory
nucleus
Gold Foil Experiment
protons
N. Bohr’s atomic theory
energy levels
quantum of energy
atomic number
mass number
isotopes
atomic mass unit (amu)
weighted atomic mass