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Ch. 2 Atoms, Molecules and Ions
For Friday Read 2.8-2.9 do example
problems
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Figure 2.18 Sodium metal reacts with chlorine
gas
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Figure 2.19 (a) Arrangement of sodium ions and
chloride ions
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Homework on Webassign

• http//www.webassign.net/
• Username perm
• Institution ucsb
• Password perm (change when you logon!)
• Access code! Not needed for 14 days
• First homework due Friday, Oct 9 at 10 PM

6
Ch. 2 Atoms, Molecules and Ions
For Friday Read 2.8-2.9 do example problems
7
Basic Principles

• Conservation of Mass
• Definite Proportions
• Multiple Proportions
• Daltons Atomic Theory
• Structure of Atoms

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Which of the following are stable compounds of
Carbon and Oxygen?
CO CO2 C2O
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Which of the following are stable compounds of
Carbon and Oxygen?
CO CO2 C2O
Are these compounds different from one another?
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Which of the following are stable compounds of
Carbon and Oxygen?
CO CO2 C2O
Law of Definite Proportion (2.2, p. 18)a given
compound always contains exactly the same
proportion of elements by mass.
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Which of the following are stable compounds of
Carbon and Oxygen?
CO CO2 C2O
Law of Multiple Proportion (2.2, p. 18)When two
elements for a series of compounds, the ratios of
the masses of the second element that combine
with 1 gram of the first element can always be
reduced to small whole numbers.
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Daltons Atomic Theory (p.19)
1. Each Element is made up of tiny particles
called atoms2. The atoms of a given element
are identical3. Chemical Compounds are formed
when atoms combine with each other. A given
compound always has the same relative s and
types of atoms4. Chemical reactions involve
reorganization of the atoms-changes in the way
they are bound together. The atoms themselves
are not changed.
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J.J. Thomson determined the charge (e) to mass
(m) ratio of the electron e/m 1.76 E 8
C/g R.Millikan determined the charge of the
electron e 1.602 E -19 C From the charge
to mass ratio and the charge of the electron,
determine the mass of an electron.
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Atoms consist of protons, neutrons, and
electrons. Draw a schematic of a carbon atom,
which has a relative mass of 12.0. Include
protons, neutrons, electrons and their charge.
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Atoms consist of protons, neutrons, and
electrons. Draw a schematic of a carbon atom,
which has a relative mass of 12.0. Include
protons, neutrons, electrons and their charge.
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