What do you know about atoms?What do you know about atoms?
• No books, no notes, no vocab.,No books, no notes, no vocab.,
complete the following:complete the following: (this is(this is
not a test)not a test)
– With the person next to youWith the person next to you
make a list of everything youmake a list of everything you
know about atoms.know about atoms.
– Draw a model of an atom.Draw a model of an atom.
Lets see your work...Lets see your work...
On the big screen!On the big screen!
Substances are madeSubstances are made
of ATOMSof ATOMS
Atomic TheoryAtomic Theory
• Atoms are the building blocks ofAtoms are the building blocks of
all matter.all matter.
• 2000 years after this was2000 years after this was
proposed we have evidence toproposed we have evidence to
support the idea but no one hassupport the idea but no one has
seen an atom.seen an atom.
Atomic ModelAtomic Model
• Old IdeaOld Idea • New IdeaNew Idea
See page 74 figures 1a and 1b
Law of DefiniteLaw of Definite
• Any sample of the same compoundAny sample of the same compound
has thehas the same elementssame elements in thein the samesame
proportionsproportions by mass.by mass.
• Example: NaCl (table salt)Example: NaCl (table salt)
– It is always 39.34% Na and 60.66% Cl by mass.It is always 39.34% Na and 60.66% Cl by mass.
– 1g of salt is 39.34% Na and 60.66% Cl.1g of salt is 39.34% Na and 60.66% Cl.
– 2000kg of salt is 39.34% Na and 60.66% Cl.2000kg of salt is 39.34% Na and 60.66% Cl.
Law of Conservation ofLaw of Conservation of
• In a chemical reaction, the massIn a chemical reaction, the mass
of the reactants = the mass of theof the reactants = the mass of the
See figure 3 page 76
• Elements: One type of atomElements: One type of atom
• Compounds: 2 or more types of atomsCompounds: 2 or more types of atoms
• This was in 1808 and he was right!This was in 1808 and he was right!
Dalton’s 5 Principles of Atomic TheoryDalton’s 5 Principles of Atomic Theory
1.1. All matter is composed of atoms.All matter is composed of atoms.
2.2. Atoms of an element are identical.Atoms of an element are identical.
3.3. Atoms of different elements differ physicallyAtoms of different elements differ physically
and chemically.and chemically.
4.4. Atoms of different elements combine in wholeAtoms of different elements combine in whole
number ratios to form compounds.number ratios to form compounds.
5.5. In a chemical reaction, atoms are combined,In a chemical reaction, atoms are combined,
rearranged, separated but NEVER created orrearranged, separated but NEVER created or
#4 of Dalton’s Principles#4 of Dalton’s Principles
• HH22O means: 2 atoms of hydrogen and 1 atomO means: 2 atoms of hydrogen and 1 atom
of oxygen combine to make 1 molecule ofof oxygen combine to make 1 molecule of
water.water. The ratio is 2:1.The ratio is 2:1.
• FeOFeO22: 1 atom of iron and 2 atoms of oxygen: 1 atom of iron and 2 atoms of oxygen
combine to form 1 molecule of iron oxidecombine to form 1 molecule of iron oxide
(rust).(rust). The ratio is 1:2The ratio is 1:2
• NOTICE!!! There are no ½ or .5, etc… OnlyNOTICE!!! There are no ½ or .5, etc… Only
whole number ratios.whole number ratios.
• List the elements and ratios for the compounds listedList the elements and ratios for the compounds listed
below. Do not try to name the compound.below. Do not try to name the compound.
There is a periodic
table in the back
cover of your
While I have your attention...While I have your attention...
Lets take a look at some of theLets take a look at some of the
problems you were having onproblems you were having on
I took these screenshotsI took these screenshots
while you were working onwhile you were working on
the “quiz” for the Particlethe “quiz” for the Particle
Nature of Matter.Nature of Matter.
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