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Do Now
A study was conducted about how many text messages SHS juniors send in a one hour class without getting caught. Out of 100 juniors, 94 were able to send 7 text messages, while the remaining juniors were able to send only 6 text messages.
What is the average number of text messages sent by these juniors?
How do we compute an averagenumber of texts?πππππ ΒΏππ πππππππ=πππ
πππππ ΒΏππ πππππ=?? ?
πππππππΒΏππ πππππ=πππππ ΒΏππ πππππ ΒΏπππππ ΒΏ
ππ πππππππ ΒΏ
β’ How many juniors sent 6 texts?100 - 94 = 6β’ How many texts were sent by the juniors who sent 7 texts?94 juniors sent 7 texts94 x 7 = 658β’ How many texts were sent by the juniors who sent 6 texts6 juniors sent 6 texts6 x 6 = 36β’ Total # of texts = 658 + 36 = 694
How do we compute an averagenumber of texts?
πππππππΒΏππ πππππ=ππππππ
=π .ππ
πππππ ΒΏππ πππππππ=πππ
πππππ ΒΏππ πππππ=πππ
πππππππΒΏππ πππππ=πππππ ΒΏππ πππππ ΒΏπππππ ΒΏ
ππ πππππππ ΒΏ
Announcementβ’ Test #2 on Atomic Theoryβ’ Wednesday, November 12, 2014β’ 40 questions, open response β’ Topics
1) Creation of the Atomic Theory
2) Subatomic Particles
3) Atomic Number, Mass Number, Atomic Mass
4) Atomic Notation
Atomic Number, Mass Number & Atomic Mass
SWBAT explain the meaning of atomic number, mass number, atomic mass and atomic symbols, and determine these features using a periodic table.
Write this in your notes
Pass OutPeriodic Tables
Save your periodic tables
You will need them for tests
Do not write anything on them
8 5.1 The Atom Has a Structure
These are called subatomic particles
Atoms are made from smaller particles!
electrons
protons
neutrons
Sub-Atomic Particles
type abbrev. location in atom
relative weight charge
change in number
produces
proton p nucleus 1 +1 different element
neutron n nucleus 1 0 isotope
electron e cloud -1 ion
How do we indicate which atom we are talking about?
β’ There are 118 different elementsβ’ Each one can have several different isotopes
and ionsβ’ Chemists needed a way of specifying exactly
which atom they were talking aboutβ’ The naming convention that evolved
specifies atoms by their subatomic particles. β’ Today we will start learning this naming
convention
11 5.1 The Atom Has a Structure
Atomic Number
Mass Number
Atomic Symbol
Atomic Mass
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12 5.1 The Atom Has a Structure
Abbreviations & Equations
p = proton
e = electron
n = neutron
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13 5.1 The Atom Has a Structure
Atomic number
atomic number: total number of protons in a nucleus.
14 5.1 The Atom Has a Structure
Atomic Number Number of protons in nucleus
Mass Number
Atomic Symbol
Atomic Mass
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15 5.1 The Atom Has a Structure
Abbreviations & Equations
p = proton
e = electron
n = neutron
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16 5.1 The Atom Has a Structure
Abbreviations & Equations
p = proton Np = number of protons
e = electron Ne = number of electrons
n = neutron Nn = number of neutrons
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17 5.1 The Atom Has a Structure
Abbreviations & Equations
p = proton Np = number of protons
e = electron Ne = number of electrons
n = neutron Nn = number of neutrons
atomic number = Z = Np Write this in your notes
18 5.1 The Atom Has a Structure
mass number: total number of protons and neutrons in a nucleus.
Mass number = 6 p + 6 n = 1212C
βcarbon-12βAlmost all of the mass of an atom
come from the protons and neutrons
19 5.1 The Atom Has a Structure
Atomic Number Number of protons in nucleus
Mass Number Number of protons and neutrons in nucleus
Atomic Symbol
Atomic Mass
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20 5.1 The Atom Has a Structure
Abbreviations & Equations
p = proton Np = number of protons
e = electron Ne = number of electrons
n = neutron Nn = number of neutrons
atomic number = Z = Np
mass number = A = Np + Nn
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21 5.1 The Atom Has a Structure
"Normal" Atomic Symbols
22 5.1 The Atom Has a Structure
"Abnormal" Atomic Symbols
Element Symbol Latin Name
Antimony Sb Stibium
Copper Cu Cuprum
Gold Au Aurum
Iron Fe Ferrum
Lead Pb Plumbum
Mercury Hg Hydragyrum
Potassium K Kalium
Silver Ag Argentum
Sodium Na Natrium
Tin Sn Stannum
Tungsten W Wolfram
Argentum
Argentina
26 5.1 The Atom Has a Structure
atomic symbol: One or two letter abbreviation for each element
27 5.1 The Atom Has a Structure
Atomic Number Number of protons in nucleus
Mass Number Number of protons and neutrons (nucleons) in nucleus
Atomic Symbol 1-2 letter abbreviation for element name
Atomic Mass
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28 5.1 The Atom Has a Structure
Capitalization
β’ The first letter of an atomic symbol is capitalized
β’ If there is a second letter, it is not capitalized
β’ Co = cobaltβ’ CO = carbon & oxygen
β’ Cl = chlorine Clβ’ CI = carbon & iodine CI
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29 5.1 The Atom Has a Structure
β’ Get out your periodic table
β’ Find lithium (atomic symbol is Li)
β’ How many protons does it have?
β’ How many neutrons does it have?
30 5.1 The Atom Has a Structure
How can lithium have 0.941 neutrons?
Periodic Table Notation
31 5.1 The Atom Has a Structure
Two lithium isotopes in nature
32 5.1 The Atom Has a Structure
Two lithium isotopes in nature
What is the massof each atom?
33 5.1 The Atom Has a Structure
Two lithium isotopes in nature
Mass number of this atom3 + 3 = 6
Mass number of this atom3 + 4 = 7
34 5.1 The Atom Has a Structure
Two lithium isotopes in nature
Mass number of this atom3 + 3 = 6
6% of natural abundance
Mass number of this atom3 + 4 = 7
94% of natural abundance
35 5.1 The Atom Has a Structure
If we randomly selected 100 lithium atoms from nature, their MASS NUMBERS would be:
Itβs an AVERAGE mass!
Atomic Mass
36 5.1 The Atom Has a Structure
Remember the "Do Now"
πππππππΒΏππ πππππ=ππππππ
=π .ππ
πππππ ΒΏππ πππππππ=πππ
πππππ ΒΏππ πππππ=πππ
πππππππΒΏππ πππππ=πππππ ΒΏππ πππππ ΒΏπππππ ΒΏ
ππ πππππππ ΒΏ
37 5.1 The Atom Has a Structure
Itβs an AVERAGE mass!
Atomic Mass
Why is this on the periodic table???β’ 6.941 g is one mole of lithium
β one mole is 6.022 x 1023 moleculesβ 6,022,000,000,000,000,000,000
β’ Chemists use this number to figure out how many molecules they have
Periodic Table Notation
38 5.1 The Atom Has a Structure
Itβs an AVERAGE mass!
Atomic Mass
Mass Number of this atom3 + 3 = 6
Mass Number of this atom3 + 4 = 7
39 5.1 The Atom Has a Structure
Atomic Number Number of protons in nucleus
Mass Number Number of protons and neutrons (nucleons) in nucleus
Atomic Symbol 1-2 letter abbreviation for element name
Atomic Mass Mass of element weighted according to natural abundance
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Calculating Atomic Charge
charge = 8 β 10 = β2 (anion)
charge = 11 β 11 = 0
charge = 11 β 10 = +1 (cation)
charge = Np β Ne
If you are given the charge,
remember Np is determined by the element
Abbreviations & Equations
p = proton Np = number of protons
e = electron Ne = number of electrons
n = neutron Nn = number of neutrons
atomic number = Z = Np
mass number = A = Np + Nn
charge = Np - Ne
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42 5.1 The Atom Has a Structure
Homework on Atomic Theory
β’ Textbook pgs 128-129β’ Problems 37, 42, 48, 51, 61
64, 65, 67, 68, 71
Check for Understanding
A new element has been discovered. It has an atomic number of 119 and a symbol of Uun. It has two different isotopes. The isotope with 178 neutrons has an abundance of 62.00%, while the remaining abundance is from an isotope with 181 neutrons.
What is the atomic mass of Uun?
How do we compute anatomic mass?
πππππππππ=?? ?ΒΏππ πππππ=? ??
ππππππππππ=πππππππππΒΏππ πππππ
ππππππππππ=?? ?
β’ Imagine we have a 100 atoms# of atoms = 100
How do we compute anatomic mass?
πππππππππ=?? ?ΒΏππ πππππ=? ??
ππππππππππ=πππππππππΒΏππ πππππ
ππππππππππ=?? ?
ΒΏππ πππππ=πππ
β’ How do we calculate the total mass of 100 atoms?add up the masses of all the isotopesβ’ How do we calculate the mass of each isotope?(mass number of isotope) x (abundance of isotope)
β’ What is the mass number of the isotope with 178 neutrons? A = Np + NnNn = 178Np = ???β’ What is the number of protons of the new element?atomic number = 119Z = Np = 119
A = 119 + 178 = 297 calledUun-297
β’ What is the mass number of the isotope with 181 neutrons? A = Np + NnNn = 181Np = 119A = 119 + 181 = 300 calledUun-300
β’ Imagine we have a 100 atoms# of atoms = 100β’ How many of these atoms are Uun-297?"abundance is 62.00"so 62 atoms are Uun-297β’ How many of these atoms are Uun-300?"the remaining abundance"100 - 62 = 38so 38 atoms are Uun-300
β’ How do we calculate the mass of each isotope?(A of isotope) x (abundance of isotope)β’ What is mass of Uun-297?(A of Uun-297) x (abundance of Uun-297)(297) x (62)β’ What is mass of Uun-300?(A of Uun-300) x (abundance of Uun-297)(300) x (38)
β’ How do we calculate the total mass of 100 atoms?add up the masses of all the isotopes(297) x (62) + (300) x (38)
ΒΏππ πππππ=πππ
How do we compute anatomic mass?
πππππππππ=?? ?
ππππππππππ=πππππππππΒΏππ πππππ
ππππππππππ=?? ?πππππππππ=(297) x (62) + (300) x (38)
How do we compute anatomic mass?
ππππππππππ=(297) x (62) + (300) x (38)
πππ
ππππππππππ=(18414 ) + (11400 )
πππ
ππππππππππ=29814πππ
ππππππππππ=πππ .ππ How many sig figs?
Check for Understanding
A new element has been discovered. It has an atomic number of 119 and a symbol of Uun. It has two different isotopes. The isotope with 178 neutrons has an abundance of 62.00%, while the remaining abundance is from an isotope with 181 neutrons.
What is the atomic mass of Uun?
How do we compute anatomic mass?
ππππππππππ=(297) x (62) + (300) x (38)
πππ
ππππππππππ β πππ .π
ππππππππππ=(18414 ) + (11400 )
πππ
ππππππππππ=29814πππ
ππππππππππ=πππ .ππ 4 sig figs
Check for Understanding
A new element has been discovered. It has an atomic number of 119 and a symbol of Uun. It has two different isotopes. The isotope with 178 neutrons has an abundance of 62.00%, while the remaining abundance is from an isotope with 181 neutrons.
What is the atomic mass of Uun? πππ .π
Review of Objective
SWBAT explain the meaning of atomic number, mass number, atomic mass and atomic symbols, and determine these features using a periodic table.
Atomic Number Number of protons in nucleus
Mass Number Number of protons and neutrons (nucleons) in nucleus
Atomic Symbol 1-2 letter abbreviation for element name
Atomic Mass Mass of element weighted according to natural abundance
Abbreviations & Equations
p = proton Np = number of protons
e = electron Ne = number of electrons
n = neutron Nn = number of neutrons
atomic number = Z = Np
mass number = A = Np + Nn
charge = Np - Ne
Check for Understanding
Potassium has two isotopes, potassium-39 & potassium-41. If the atomic mass is 39.10, what is the natural abundance of each isotope?X = abundance of A = 39
1 β X = abundance of A = 41
39.10 = (X)(39) + (1βX)(41)
39.10 = 39X + 41 β 41X
39.10 = β2X + 41
β1.90 = β2X
0.95 = X
95% A = 39, 5% A = 41
How do we compute anatomic mass?
πππππππππ=?? ?ΒΏππ πππππ=? ??
ππππππππππ=πππππππππΒΏππ πππππ
ππππππππππ=ππ .ππ
β’ Imagine we have a 100 atoms# of atoms = 100
How do we compute anatomic mass?
πππππππππ=?? ?ΒΏππ πππππ=πππ
ππππππππππ=πππππππππΒΏππ πππππ
ππππππππππ=ππ .ππ
β’ Imagine we have a 100 atoms# of atoms = 100β’ Set the # of potassium-39 atoms to be "y"# of potassium-39 = yβ’ The # of potassium-41 would be "100 - y"# of potassium-41 = 100 - y
β’ The mass of all the potassium-39 atoms is found as follows:(# of potassium-39) x (mass of potassium-39)(y) x (39)39yβ’ The mass of all the potassium-41 atoms is found as follows:(# of potassium-41) x (mass of potassium-41)(100 β y) x (41)4100 β 41y
β’ The total mass of all the potassium atoms is found as follows: total mass of potassium-39 + total mass of potassium-41total mass of potassium atoms 39y + 4100 β 41y4100 β 2 y
How do we compute anatomic mass?
πππππππππ=ππππ βπ πΒΏππ πππππ=πππ
ππππππππππ=πππππππππΒΏππ πππππ
ππ .ππ=ππππ βπ π
πππ
ππππππππππ=ππ .ππ
βπππ=βπ π
ππ .ππ=ππππ βπ π
πππ
ππππ=ππππ βπ π
ππ=π
β’ Set the # of potassium-39 atoms to be "y"# of potassium-39 = y or 95% are potassium-39β’ The # of potassium-41 would be "100 - y"# of potassium-41 = 100 - y100 - 95 = 5 or 5% are potassium-41
Weighted Average
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