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© 2012 Pearson Education, Inc.
CH 4 : THE ATOM
On the first right side page (after Ch 3 notes):
• Create a Cover page for Chapter 4.
• Make atom design the whole page and label the
parts of the atom.
• Include COLOR!
• I have a sample one online you can use
On the back side of cover page (left side),
• Paste in the “I can” Learning Objectives #10-22.
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© 2012 Pearson Education, Inc.
TN Ch 4.1 Date
Title and
Highlight
Topic:
EQ:
NOTES:
Write out the notes from my website.
Use different types of note-taking
methods to help you recall info (different
color pens/highlighters, bullets, etc)
When I lecture we will add more info, so
leave spaces in your notes
Summary Questions:
2-3 sentences… What did you learn
today from the notes?
THESE ARE AT THE VERY END OF
NOTES
Right Side – NOTES ONLY
Reflect
Question:
Reflect on
the
material by
asking a
question
(its not
suppose to
be
answered
from
notes)
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© 2012 Pearson Education, Inc.
TN Ch 4.1
Title and
Highlight
DRAW ANY PICTURES, FIGURES,
AND WRITE OUT ANY PRACTICE
PROBLEMS/QUESTIONS.
WE WILL ANSWER THEM TOGETHER.
LEAVE SPACES SO WE CAN ANSWER
QUES.
LEFT Side – PICTURES, PRACTICE PROBLEMS, ETC
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© 2012 Pearson Education, Inc.
TOPIC: ATOMIC THEORY
EQ: Explain the history & the discovery of the atom
Ch 4.1-4.2
READ Ch 4.1-4.2 (pg. 93-95) first then write notes
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© 2012 Pearson Education, Inc.
CH 4.1 ATOMS • Atoms are incredibly small.
• To get an idea of how small atoms are: • if every atom within
a small pebble were the size
of the pebble itself, the pebble would be larger than Mount
Everest.
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© 2012 Pearson Education, Inc.
ATOMS AND ELEMENTS• ATOM - “Building Blocks of Matter”• An atom
is the smallest particle of an element that retains the chemical
properties of that element.
• An element is a substance that cannot be broken down into
simpler substances.
• There are about 91 different elements in nature, and
consequently about 91 different kinds of atoms. (The other 27 are
synthetic – man made elements)
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© 2012 Pearson Education, Inc.
CH 4.2
The Atom: From Philosophical Idea to Scientific Theory
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© 2012 Pearson Education, Inc.
THE EARLY ATOM
• As early as 400 B.C., Democritus called nature’s basic
particle the “atomon” based on the Greek word meaning
“indivisible”.
• His theory: Matter could not be divided into smaller pieces
forever, eventually the smallest possible piece would be
obtained.
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© 2012 Pearson Education, Inc.
ATOMS
▪To Democritus, atoms were small, hard particles that were all
made of the same material but were different shapes and sizes.
▪Atoms were infinite in number, always moving and capable of
bonding together.
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© 2012 Pearson Education, Inc.
THE EARLY ATOM
• Most influential philosopher, Aristotle rejected Democritus’
atom theory b/c different from his ideas
• Criticized Democritus’ idea that atoms moved through empty
space
• Aristotle succeeded Democritus and did not believe in atoms.
Instead, he thought that all matter was continuous. It was his
theory that was accepted for the next 2000 years.
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© 2012 Pearson Education, Inc.
WHY?
• In the end….. Aristotle was wrong in the end.
Aristotle favored
the earth, fire, air
and water
approach to the
nature of matter.
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© 2012 Pearson Education, Inc.
DALTON’S ATOMIC THEORY• John Dalton (1766-1844)
• English Chemist and schoolteacher
• In 1808,performed a number of experiments that led to the idea
of atoms…..over 2000 years later after Democritus/Aristotle
theory.
I was a
school
teacher at
the age of
12!
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© 2012 Pearson Education, Inc.
DALTON’S ATOMIC THEORY
1. All matter is composed of extremely small particles called
atoms.
2. Atoms of a given element are identical in size, mass, and
other properties.**
3. Atoms cannot be subdivided, created, or destroyed.**
4. Atoms of different elements combine in simple whole-number
ratios to form chemical compounds.
5. In chemical reactions, atoms are combined, separated, or
rearranged.
**Today, we know these parts to be wrong!!
http://tm.ask.com/r?t=c&s=p&sv=0a30052b&uid=0BC1ACC9982C64134&sid=3444474eb444474eb&o=0&id=30751&p=/fr&u=http://www.juliantrubin.com/imagesc/dalton1.gif
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© 2012 Pearson Education, Inc.
• Was Dalton’s theory a huge step toward our current model of
matter?
• Yes!!! It was a breakthrough in our understanding of
matter.
• Was all of Dalton’s theory accurate?
• No!!!
Dalton’s Atomic Theory
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© 2012 Pearson Education, Inc.
FLAWS OF DALTON’S THEORY…
#2. Atoms of a given element are identical in size, mass, and
other properties.
#3. Atoms cannot be subdivided, created, or destroyed.
Isotopes – atoms with the same
number of protons but a different
number of neutrons
Subatomic particles – electrons,
protons, neutrons, and more
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© 2012 Pearson Education, Inc.
SUMMARY:
Let’s reflect….
What did you learn today from the notes?
(2-3 sentences)
RIGHT side - THESE ARE AT THE VERY END OF NOTES
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© 2012 Pearson Education, Inc.
TOPIC: SUBATOMIC PARTICLES
EQ: Explain the history & the discovery of the 3 subatomic
particles in an atom
Ch 4.3
READ Ch 4.3 (pg. 95-97) first then write notes
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CH 4.3 - DISCOVERY OF THE SUBATOMIC PARTICLES
• The discovery of the subatomic particles came about from the
study of electricity & matter.
• Benjamin Franklin’s kite experiment in 1752 demonstrated that
lightning was electrical.
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DISCOVERY OF THE ELECTRON
• 1870’s - many experiments were performed in which electric
current was passed through gases at low pressures
• These experiments were carried out in glass tubes called
cathode-ray tubes.
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Electric CurrentElectric Current
Draw this with
notes in color!!!
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© 2012 Pearson Education, Inc.
DISCOVERY OF THE ELECTRON
• The rays traveled from cathode (negative) to anode
(positive).
• Negatively charged objects deflected the rays away.
• Therefore, it was determined that the particles making up the
cathode rays were negatively charged.
http://tm.ask.com/r?t=an&s=p&uid=0BC1ACC9982C64134&sid=3444474eb444474eb&o=0&qid=76FE87617A9172D61596A95907E4D87D&io=4&sv=0a300518&ask=crookes+tube&uip=444474eb&en=is&eo=&pt=&ac=24&qs=31&pg=2&u=http://web.ask.com/fr?q%3Dcrookes%2Btube%26desturi%3Dhttp://www.ihep.ac.cn/kejiyuandi/zhishi/green/green-index.htm%26fm%3Di%26ftURI%3Dhttp://pictures.ask.com:80/fr?q%3Dcrookes%2Btube%26desturi%3Dhttp://www.ihep.ac.cn/kejiyuandi/zhishi/green/green-index.htm%26imagesrc%3Dhttp://www.ihep.ac.cn/kejiyuandi/zhishi/green/crookes-tube_small.jpg%26thumbsrc%3Dhttp://images.picsearch.com/is?7001082979393%26thumbwidth%3D128%26thumbheight%3D71%26fn%3Dcrookes-tube_small.jpg%26f%3D2%26fm%3Di%26ftbURI%3Dhttp%3A%2F%2Fpictures.ask.com%2Fpictures%3Fq%3Dcrookes%2Btube%26page%3D2%26qt%3D0
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© 2012 Pearson Education, Inc.
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© 2012 Pearson Education, Inc.
THOMSON’S PLUM PUDDING MODEL
• In 1897, the English scientist J.J. Thomson provided the first
hint that an atom is made of even smaller particles.
(1908 Nobel Prize in Chemistry)
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© 2012 Pearson Education, Inc.
THOMSON’S PLUM PUDDING ATOMIC MODEL
Thomson believed that the electrons were like plums
embedded in a positively charged “pudding,” thus it
was called the “plum pudding” model.
Draw this with
notes in color!!!
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© 2012 Pearson Education, Inc.
• So….. J. J. Thomson discovered the electron.
• found that e- are negatively charged.
• e- are much smaller and lighter than atoms.
• every element (atom) has e-.
• He proposed that atoms must contain + charge that balanced the
- charge of electrons.
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© 2012 Pearson Education, Inc.
Millikan’s Oil Drop
Experiment
Robert Millikan (1909): Millikan’s Oil-drop ExperimentDiscovered
the mass and charge on the electronCharge of electron: -1
Mass of electron = 9.1 x 10-28 g
004_MILLIKANOIL.MOV004_MILLIKANOIL.MOVfile:///C:/1213 School
Year/Honors Chemistry/Chapter 2 Atoms Molecules Ions/flash
shockwave animations/02_Millikan_Oil_Drop.swf
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© 2012 Pearson Education, Inc.
RUTHERFORD’S GOLD FOIL EXPERIMENT• 1911 - English
physicist Ernest Rutherford
• Rutherford’s experiment involved firing a stream of tiny
positively charged alphaparticles at a thin sheet of gold foil(2000
atoms thick)
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© 2012 Pearson Education, Inc.
RUTHERFORD’S FINDINGS• Most of the positively
charged particles passed through the gold foil without changing
course.
• Some of the positively charged particles did bounce away from
the gold sheet as if they had hit something solid.
Draw this with
notes in color!!!
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© 2012 Pearson Education, Inc.
(1) Most of the atom is more or less ______ _______.
(2) The nucleus is very _________ and ___________.
(3) The nucleus is ______________ charged due to protons.
(4) The nucleus (protons and neutrons) is 99.97% of an atom’s
mass.
(5) The electron cloud = majority of volume
• SO……. atoms is neutral: the positive (nucleus) balances out
the negative electrons
• So, why do electrons stay surrounded around the nucleus?
“Opposites attract”
empty space
densetiny
positively
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© 2012 Pearson Education, Inc.
A SUMMARY OF THE NATURE OF ELECTRICAL CHARGE•Positive and
negative
electrical charges attracteach other.
•Positive–positive and negative–negative charges repel each
other.
•Positive and negative charges cancel each other so that a
proton and an electron, when paired, are charge-neutral.
Draw this with
notes in color!!!
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© 2012 Pearson Education, Inc.
Rutherford’s Model of
the Atom
2.2
Draw this with
notes!!!
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© 2012 Pearson Education, Inc.
James Chadwick (1932)
Discovered the neutron.
The neutron has about the same mass as
the proton.
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© 2012 Pearson Education, Inc.
• After the proton & electron was discovered….
• The Neutron was discovered last (almost 30 years later) out of
all the subatomic particles, why?
• Scientist knew the charge of nucleus (+) and knew the mass of
nucleus (came from proton). But their calculations were off by
half…. could not figure out why the nucleus was so heavy if the
proton only had a certain mass.
• There must be a third subatomic particle that weighed as much
as a proton, but with no charge!
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© 2012 Pearson Education, Inc.
Democristus
400BC
Aristotle
4 elements
Dalton (1803)
Atomic Theory
Thomson (1897)
Plum Pudding Model
Cathode Ray Tube
electrons
Rutherford (1911)
Gold Foil Experiment
Proton & Nucleus (Mass and Volume)
Millikan (1909)
Charge & Mass
of electron
Chadwick (1932)
Neutron
THE ATOM - TIMELINE Draw this left side!!!
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© 2012 Pearson Education, Inc.
SUMMARY:
Let’s reflect….
What did you learn today from the notes?
(2-3 sentences)
RIGHT side - THESE ARE AT THE VERY END OF NOTES
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© 2012 Pearson Education, Inc.
TOPIC: THE STRUCTURE OF THE ATOM
EQ: What is the difference between protons, neutrons, and
electrons?
Ch 4.4
READ Ch 4.4 (pg. 97-99) first then write notes
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© 2012 Pearson Education, Inc.
THE ATOM
• Atom - the smallest particle of an element.
• How small is an atom?
• Copper atoms in penny –29,000,000,000,000,000,000,000 (2.9 x
1022)
Copper
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© 2012 Pearson Education, Inc.
THE STRUCTURE OF THE ATOM
• The atom is composed of two main regions: the nucleus &
the electron cloud.
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© 2012 Pearson Education, Inc.
THE ATOM
• The atom is made up of three subatomic particles.
Draw this with
notes in
color!!!
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© 2012 Pearson Education, Inc.
NUCLEUS OF AN ATOM
• Nucleus- VERY small region located at the center of the atom.
The nucleus accounts for most of an atoms mass but very little
volume, making it a very dense region.
• The nucleus contains protons & neutrons.
proton = p+ neutron = no
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© 2012 Pearson Education, Inc.
ELECTRON CLOUD OF AN ATOM
• The electron cloud is the negatively charged region of the
atom that accounts for most of the atom’s volume but very little of
the atom’s mass.
electron = e-
The electron cloud is
composed of electrons.
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© 2012 Pearson Education, Inc.
SUBATOMIC PARTICLESParticle Symbol Location Electrical
charge
Mass
(amu)
Actual
Mass (g)
Electron e- Outside
nucleus
-1 1/1840 9.11x10-28
(About 2000
times smaller
than Proton
and neutron)
Proton p+ Nucleus +1 1
1.67x10-24
Neutron n0 nucleus 0 1
1.67x10-24
They have the SAME Mass
Draw this left
side!!!
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© 2012 Pearson Education, Inc.
PRACTICE PROBLEMS #1
❑ What are the two main regions of the atom?
❑What is the charge on the nucleus?
left side!!!
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© 2012 Pearson Education, Inc.
SUMMARY:
Let’s reflect….
What did you learn today from the notes?
(2-3 sentences)
RIGHT side - THESE ARE AT THE VERY END OF NOTES
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© 2012 Pearson Education, Inc.
TOPIC: ELEMENT NAMES, SYMBOLS, & THE STRUCTURE OF THE
ATOM
EQ: How do you write an element’s symbol? How many p+, no, &
e- does
any element have?
Ch 4.5
READ Ch 4.5 (pg. 99-101) first then write notes
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© 2012 Pearson Education, Inc.
CH 4.5: CHEMICAL SYMBOLS• Chemists use chemical symbols to
represent elements.
• The chemical symbol consists of 1 or 2 letters.
• The first letter ALWAYS ______________.
• The next letter is _______________.
capitalized
lowercase
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© 2012 Pearson Education, Inc.
CH 4.5 ELEMENTS: ORIGINS OF THE NAMES OF THE ELEMENTS
• Most chemical symbols are based on the English name of the
element.
• Some symbols are based on Greek or Latin names, which include
the following:
potassium K kaliumsodium Na natriumlead Pb plumbummercury Hg
hydrargyrumiron Fe ferrumsilver Ag argentumtin Sn stannumcopper Cu
cuprum
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© 2012 Pearson Education, Inc.
JUST READ!!!!• Early scientists gave newly discovered
elements names that reflected their properties:
• Argon, from the Greek argos, means “inactive,” referring to
argon’s chemical inertness.
• Other elements were named after countries:
• Polonium after Poland • Francium after France• Americium after
the United States of
America.
• Other elements were named after scientists. • Curium after
Marie Curie• Einstenium after Albert Einsten
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© 2012 Pearson Education, Inc.
THE PERIODIC TABLE OF THE ELEMENTS LISTS ALL KNOWN ELEMENTS
ACCORDING TO THEIR ATOMIC
NUMBERS.
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© 2012 Pearson Education, Inc.
• The # of protons in the nucleus of an atom that identifies an
element.
• The # of protons in the nucleus of an atom is its atomic
number.
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© 2012 Pearson Education, Inc.
SYMBOL NOTATION
XMass
number
Atomic
numberSubscript →
Superscript →
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© 2012 Pearson Education, Inc.
Atomic number (Z).
Protons determines the identity of the element.
A# = p+ = e- (atoms are neutral)
The Mass Number (A),
(rounded to the nearest
integer)
Mass# = p+ + no
A is always the largernumber than Z.
# of neutrons = mass number – # p+
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© 2012 Pearson Education, Inc.
LOOK FOR THE ELEMENT CHLORINE…..
LET’S WRITE HIS CHEMICAL SYMBOL
NOTATION
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© 2012 Pearson Education, Inc.
Cl35
17
MASS
NUMBER
ATOMIC
NUMBER
NUMBER OF
PROTONS
# PROTONS+
# NEUTRONS
Symbol notation
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© 2012 Pearson Education, Inc.
LOOK FOR THE ELEMENT CARBON…..
LET’S WRITE HIS CHEMICAL SYMBOL
NOTATION
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© 2012 Pearson Education, Inc.
SYMBOL NOTATION
Element followed by a hyphen – mass#
Carbon-12
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© 2012 Pearson Education, Inc.
• Difference between Mass and Atomic weight
• Atomic weight is the weight of all the isotopes for that
element (decimal #)
• Mass number is the rounded number for the atomic weight.
• Example: Copper
• Atomic weight – 63.546
• Mass number - 63
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© 2012 Pearson Education, Inc.
PRACTICE PROBLEMS
Element Atomic
#
Mass
#
p + n o e - Symbol
Oxygen - 8
33 42
-31 31 15
91 140
Sodium - 23
Uranium - 238
80
Br
35
26
Mass number
left side
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© 2012 Pearson Education, Inc.
SUMMARY:
Let’s reflect….
What did you learn today from the notes?
(2-3 sentences)
RIGHT side - THESE ARE AT THE VERY END OF NOTES
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© 2012 Pearson Education, Inc.
TOPIC: ISOTOPES
EQ: What is an isotope and how does it affect the atom?
Ch 4.8
READ Ch 4.8 (pg. 109-111) first then write notes
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© 2012 Pearson Education, Inc.
4.8 ISOTOPES: WHEN THE NUMBER OF NEUTRONS
VARIES
• All atoms of an element have the same # of protons.
• They do not have the same # of neutrons.
• Atoms with the same # of protons but different # of neutrons
are called isotopes.
• Example Hydrogen
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© 2012 Pearson Education, Inc.
ISOTOPES
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© 2012 Pearson Education, Inc.
EXAMPLE OF AN ISOTOPE
Cl35
17 Cl37
17
20 NEUTRONS
ATOMIC MASS
18 NEUTRONS
ATOMIC NUMBER
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© 2012 Pearson Education, Inc.
Review…. How to write Symbol Notation
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© 2012 Pearson Education, Inc.
Practice Problem #1
Circle which of the following are isotopes.
40
20 X40
18 X42
20 X40
19 X43
20 X
left side!!!
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© 2012 Pearson Education, Inc.
Practice Problem #2
Determine the number of protons, neutrons and electrons in the
neutral (non-charged) isotopes of the following atoms:
88
38 Sr84
38 Sr
left side!!!
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© 2012 Pearson Education, Inc.
SUMMARY:
Let’s reflect….
What did you learn today from the notes?
(2-3 sentences)
RIGHT side - THESE ARE AT THE VERY END OF NOTES
-
© 2012 Pearson Education, Inc.
TOPIC: AVERAGE ATOMIC MASS
EQ: How do you calculate average atomic mass?
Ch 4.9
READ Ch 4.9 (pg. 111-113) first then write notes
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© 2012 Pearson Education, Inc.
Average Atomic Mass
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© 2012 Pearson Education, Inc.
• The atomic masses listed in the Periodic Table are a “weighted
average” of all the isotopes of the element.
• Units = atomic mass unit (amu)
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© 2012 Pearson Education, Inc.
In general, atomic mass is calculated according to the following
equation:
Average Atomic mass =
Step 1: Convert the percent natural abundances into decimal form
by dividing by 100.
Step 2: Multiply the decimal abundances with the isotopes
mass.
Step 3: Add up the atomic masses for each isotope. This is the
average atomic mass for that element (should be close to the number
listed on P.T.)
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© 2012 Pearson Education, Inc.
• All elements have their own unique percent natural abundance
of isotopes.
• Naturally occurring chlorine consists of
75.77% chlorine-35 (mass 34.97 amu) and 24.23% chlorine-37 (mass
36.97 amu).
• Which isotope is the most abundant?
• What is the Average Atomic Mass of Cl?
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© 2012 Pearson Education, Inc.
• Gallium has two naturally occurring isotopes: Ga-69, with mass
68.9256 amu and a natural abundance of 60.11%, and Ga-71, with mass
70.9247 amu and a natural abundance of 39.89%. Calculate the atomic
mass of gallium.
Left side: Leave 5 lines of space to solve in class
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© 2012 Pearson Education, Inc.
• Write Question #97 from textbook
Left side: Leave 5 lines of space to solve in class
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© 2012 Pearson Education, Inc.
SUMMARY:
Let’s reflect….
What did you learn today from the notes?
(2-3 sentences)
RIGHT side - THESE ARE AT THE VERY END OF NOTES