Download Atoms, Ions and Molecules

Atoms, Ions and
Molecules
Chapter 2
Jodi Grack; Wayzata High School;
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Ch. 2 – Atoms, Ions and Molecules
2.1 The Early History of Chemistry Ancient Greeks - thought matter was composed to
4 substances – earth, air, fire, water
(___________ vs. ___________)
Alchemy - _______________________________
discovered many elements; learned to prepare
mineral acids
Metallurgy - extraction of metals from ore
Jodi Grack; Wayzata High School;
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Ch. 2 – Atoms, Ions and Molecules
2.1 The Early History of Chemistry cont.Robert Boyle - (1661 - Skeptical Chymist) - first
quantitative experiments; current concept of
“element”
Georg Stahl – suggested “phlogiston” flowed out
of burning material
Joseph Priestley - (1733-1804) “discovered”
oxygen (not phlogiston)
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2.2 - 2.3 Fundamental Chemical
Laws/ Dalton’s Atomic Theory NATURAL LAWS:
1. Conservation of
Mass - In any
chemical reaction,
mass is neither
created nor destroyed
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2.2 - 2.3 Fundamental Chemical
Laws/ Dalton’s Atomic Theory NATURAL LAWS:
2. Constant Composition – a given
compound always contains exactly the
same proportion of elements by mass.
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2.2 - 2.3 Fundamental Chemical
Laws/ Dalton’s Atomic Theory NATURAL LAWS:
3. Multiple Proportions - When two elements form a series
of compounds, the ratios of the masses of the 2nd element
that combine with 1 gram of the 1st element can always
be reduced to small whole numbers.
Jodi Grack; Wayzata High School;
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2.2 - 2.3 Fundamental Chemical
Laws/ Dalton’s Atomic Theory NATURAL LAWS:
3. Multiple Proportions - When two elements form a series
of compounds, the ratios of the masses of the 2nd element
that combine with 1 gram of the 1st element can always
be reduced to small whole numbers.
Mass Nitrogen
w/ 1 g O
Mass Oxygen
w/ 1 g C
Cpd I
Cpd II
1.33 g
2.66 g
Cpd I
Cpd II
Cpd III
1.750 g
0.8750 g
0.4375 g
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2.2 - 2.3 Fundamental Chemical
Laws/ Dalton’s Atomic Theory John Dalton (1808) “Father of Atomic Theory”
Essentials of his theory. . .
1. An element is composed of tiny particles called atoms.
All atoms of a given element show the same chemical
properties.
2. Atoms of different elements have different properties. In
an ordinary chemical reaction, no atom of any element
disappears or is changed into an atom of another
element.
3. Compounds are formed when atoms of two or more
elements combine. In a given compound, the relative
numbers of atoms of each kind are definite and
constant. In general, these relative numbers can be
expressed as integers
simple
fractions.
Jodi Grack;or
Wayzata
High School;
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2.2 - 2.3 Fundamental Chemical
Laws/ Dalton’s Atomic Theory IN GENERAL Elements consist of tiny particles called
_________, which retain their identity in
___________________. In a compound,
atoms of two or more elements are
combined in a fixed ratio of
____________________________.
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Gay-Lussac - (1809) Combining Volumes of Gases
• Performed experiments in which he measured
(under same T & P) the ___________________
Jodi Grack;
Wayzata
High School;
that reacted with
each
other.
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2.2 - 2.3 Fundamental Chemical
Laws/ Dalton’s Atomic Theory Amadeo Avogadro - (1811) “Avogadro’s
Hypothesis”
• Equal volumes of different gases contain
the _____________________________
at the same temperature and pressure.
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2.4 Early Experiments to
Characterize the Atom
JJ Thomson (1856 - 1940): English physicist
____________ Experiment (late 1890’s)
Important Observations
Inferences
This lead to theJodi_____________
Model
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2.4 Early Experiments to
Characterize the Atom
Robert Milikan (1868 - 1953)
_____________ Experiment (1909)
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Important Observations
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Inferences
2.4 Early Experiments to
Characterize the Atom
Sir James Chadwick (1891-1974):
confirmed existence of ____________
Henri Bequerel (1896) French Chemist
essentially discovered ________________
(alpha, beta, and gamma particles
discovered later)
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2.4 Early Experiments to
Characterize the Atom
Ernest Rutherford (1911)
________________ experiment
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2.4 Early Experiments to
Characterize the Atom
Important Observations
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Inferences
2.5 - 2.6 Modern View of Atomic
Structure/ Molecules and Ions COMPONENTS
Proton
Neutron
Electron
Relative
Mass
_____
_____
_____
Relative
Charge
_____
_____
_____
Actual
Location Mass
_______ 1.6727 x 10-24 g
_______ 1.6750 x 10-24 g
_______ 9.1095 x 10-28 g
Actual
Charge
1.6022 x 10-19 C
__0____
-1.6022 x 10-19 C
A X
Nuclear Symbol
(X = element symbol)
Z
• Z = Atomic Number = number of protons and is UNIQUE
• A = Mass Number = sum of neutrons and protons
is NOT unique
• Atoms and Molecules are
electrically neutral ---> # protons = # electrons
Jodi Grack; Wayzata High School;
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2.5 - 2.6 Modern View of Atomic
Structure/ Molecules and Ions Ions - Have an electrical charge due to gain/loss
of electrons
cations anions –
isoelectric K+, Ca2+, P3-, S2-, Cl-, Ar
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2.5 - 2.6 Modern View of Atomic
Structure/ Molecules and Ions Isotopes Isotope
Mg-24
Mg-25
Mg-26
Mass (amu)
23.9850
24.9858
25.9826
Percent (Abundance)
78.99%
10.00%
11.01%
Determine the relative average atomic weight of Magnesium.
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2.5 - 2.6 Modern View of Atomic
Structure/ Molecules and Ions COMPLETE THE FOLLOWING TABLE:
31 P
15
_____ _____
_____ _____
H3O+
_____
# p+ _____ _____
_____ _____
_____
# no _____ _____
_____ _____
_____
# e-
40Ca2+
74As3-
38F
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2
The Periodic Table
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Naming Compounds
IONIC
Metal and Nonmetal
(+) ion and (-) ion
1) Correctly name the metal ion.
• If the Metal is from Group IA, IIA (or is Aluminum, Zinc, Cadmium, or
Silver) the charges can be predicted thus no Roman numerals are needed
• All other metals have more than one possible charge and thus you DO need
roman numerals
2) Correctly name the nonmetal ion.
• Use stem of element name and add '-ide"
OR
• Simply cite the name of the polyatomic ion
Ex.
CaCl2
Calcium chloride
Be(NO2) 2
Beryllium nitrite
MnS
Manganese (II) sulfide
CoCl3
Cobalt (III) chloride
Silver Sulfide
Ag2S
ZnSO4
Zinc sulfate
JodiCopper
Grack; Wayzata
High School;
CuOH
(I) hydroxide
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Naming Hints
NAMING POLYATOMIC IONS
NO3-
SO42-
PO43-
NO2-
SO32-
PO33-
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Naming Hints
NAMING POLYATOMIC IONS
ClO4ClO3ClO2ClO1Jodi Grack; Wayzata High School;
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Naming Practice
1) K2O
2) MnS
3) Ca(NO3)3
4) FeO
Jodi Grack; Wayzata High School;
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MOLECULAR (binary only)
all nonmetals
• Use prefixes to indicate the number of atoms of each element. (Omit monofrom first element.)
1 - mono
2 - di
3 - tri
4 - tetra
5 - penta
6 - hexa
7 - hepta
8 - octa
9 - nona
10 - deca
• Name the first element using the correct prefix.
Name second element by using the stem and adding -ide.
Ex.
CO
CO2
SF6
N2O4
PCl5
H2O
carbon monoxide
carbon dioxide
Sulfur hexafluoride
dinitrogen tetroxide
phosphorous pentachloride
dihydrogen monoxide
NOTE: When the second element is oxygen, drop the last vowel in the prefix
(except for di- and tri-)
Ex.
N2O4
P2O5
CO
NO2
SO3
dinitrogen tetroxide (not tetraoxide)
diphophorus pentoxide (not pentaoxide)
carbon monoxide (not monooxide)
nitrogen dioxide
Jodi Grack; Wayzata High School;
sulfur trioxide
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Naming Acids
ACIDS
Binary Acids
Hydro(anion root)ic acid
Oxyacids
If the polyatomic ion contains
-ate Æ (root)ic acid
-ite
Æ (root)ous acid
HCl
HI
H2SO4 Sulfuric Acid
H2SO3 Sulfurous Acid
hydrochloric acid
hydroiodic acid
Jodi Grack; Wayzata High School;
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