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CHAPTER 2 ATOMS,
MOLECULES AND IONS
CHAPTER 2 CONTENTS
•
Sec 2.4 Atomic Weights
•
Sec 2.5 Periodic Table of the Elements
–
–
•
Identify group name, period and group number of an element.
Sec 2.2 The Structure of the Atom
–
•
Calculate the average atomic weight of any naturally occurring element.
Be familiar with the parts of the atom, how they were discovered and by whom.
Sec 2.3 Nuclear Structure: Isotopes
–
Write the symbol of any nuclide.
Classifying Matter
Matter
Substances
Elements
Mixtures
Compounds
Homogeneous
Heterogeneous
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Distinguish between elements,
compounds and mixtures
Book Depiction of Atoms and
Molecules
Scanning Tunneling Microscope
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Actual Pictures of Atom/Molecules
from STM
Nanotechnology
• Scanning Electron Micrscope
http://video.google.com/videoplay?docid=7586933550696352328&ei=buq_SLKWHJSur
gKvoqGJCQ&q=electron%2Bmicroscope&vt=l
f&hl=en
Solids, Liquids and Gases:
States of Matter
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Identify and differentiate between
physical and chemical properties of
substances and mixtures.
• Adjectives that
describe
appearance
– Examples:
Size, shape,
color, state,
melting point,
density, etc
•How a
substance reacts
in the presence
of another
-Examples:
Burning, rusting,
tarnishing,
decomposing,
etc
Calculate the average atomic mass
of any naturally occurring element.
Σ Isotopic Mass x Fractional Abundance
For each
isotope
Average Atomic Mass Example
• The isotopic composition of a certain element X
is 80% 24X, 10% 25X and 10% 26X.
The relative-atomic mass of X is
A.
B.
C.
D.
24.67
24.33
24.25
24.30
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Average Atomic Mass
The Mass Sprectrometer
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The Periodic Table
Information from Periodic Table
Identify group name, period and
group number of an element.
• Potassium?
• Chlorine?
• Xenon?
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Information from Periodic Table
Atomic Number (Z)
AverageAtomic Mass (A)
Write the symbol of any nuclide.
• Hyphenated Nuclide Symbol
Example:Chlorine-35
Format:
Element Name-A
• Nuclear Symbol
Example: 35
17
Cl
Format:
Be familiar with the parts of the
atom, how they were discovered
and by whom.
• Electron Charge
– JJ Thomson:
http://www.youtube.com/watch?v=XU8nMKkz
bT8
– Robert Millikan
http://www.youtube.com/watch?v=91E6KvCv
Rf0
http://www.youtube.com/watch?v=XMfYHag7
Liw
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Be familiar with the parts of the
atom, how they were discovered
and by whom.
• Nucleus and the Proton
– Ernest Rutherford
http://www.youtube.com/watch?v=Q8RuO2ek
NGw
– James Chadwick
http://www.youtube.com/watch?v=DTnCkcVO
KSE
June 30, 2008, 6:47 PM CT
Physicists create millimeter-sized 'Bohr atom'
HOUSTON -- June 30, 2008 -- Nearly a century
after Danish physicist Niels Bohr offered his planetlike model of the hydrogen atom, a Rice Universityled team of physicists has created giant, millimetersized atoms that resemble it more closely than any
other experimental realization yet achieved.
Using laser beams and electric
fields, Rice physicists coaxed a
point-like, "localized" electron to
orbit far from the nucleus of a
potassium atom.
Credit: Jeff Mestayer/Rice
University
The research is available online in Physical Review
Letters
Bohr offered the first successful theoretical model
of the atom in 1913, suggesting that electrons
traveled in orbits around the atom's nucleus like
planets orbiting a star. Bohr's model led to a deeper
understanding of both the chemical and optical
properties of atoms and won him a Nobel Prize in
1922. But his notion of electrons traveling in
discrete orbits was eventually displaced by
quantum mechanics, which revealed that electrons
don't have precise positions but are instead
distributed in wave-like patterns.
It doesn’t stop at p,n,e
• What we now know….
– http://www.youtube.com/watch?v=SMgi2j9Ks9k
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Dates to Remember
• Unit 2 Exam on Wednesday, Sept 2
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