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Atoms: The Building Blocks of Matter. Unit 2. Introduction to the Atom Modern Atomic Theory Subatomic Particles Isotopes Ions. Essential Standards and objectives: 1.1.1 Analyze the structure of atoms, isotopes, and ions. 1.1.2 Analyze an atom in terms of the location of electrons. - PowerPoint PPT Presentation
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Atoms: The Building Blocks of MatterUnit 2
Introduction to the Atom Modern Atomic Theory Subatomic Particles Isotopes Ions
Essential Standards and objectives:1.1.1 Analyze the structure of atoms, isotopes, and ions.1.1.2 Analyze an atom in terms of the location of electrons.1.1.3Explain the emission of electromagnetic radiation in spectral form in terms
of the Bohr model.1.1.4 Explain the process of radioactive decay using nuclear equations and half-life. 2.2.5 Analyze quantitatively the composition of a substance. (Introduction to moles)
The Atom: Smallest particle of an element that retains the chemical properties of the element.
Essential Questions:
What is an atom?
What is its structure?
What determines properties of an element?
Atoms act in orderly, predictable ways.
PHET Build an Atom Use this in the search window Share a computer with a partner Individual work (write your answers on a
separate paper) http://phet.colorado.edu/en/simulation/build-
an-atom
Explain:
How does this graphic demonstrate the characteristics of an atom?
Make sure that you include each graphic (portions) in your explanation
Reading: Cornell notesEssential questions: What are the characteristics
of an atom?
In your notes: address both individual atoms and atoms of an element
Modern Atomic Theory1. All matter:
2. Atoms of a given element:
3. Atoms cannot be created nor destroyed in:
4. In chemical reactions, atoms are
Atomic Theory (cont.) 5. To form compounds:
Law of Definite Proportions
Law of Multiple Proportions
Summary Table: Atomic Structure- Subatomic Particles
Subatomic Location Charge Mass Importance
Particle AMU
Designation of Atomic Structure Atomic number (Z):
On the Periodic Table:
Mass number (A): On the Periodic Table:
Representing atoms Information from symbols and the Periodic
Table
What does this symbol tell us?
Protons:
Neutrons:
Electrons:
Designations for the Atomic
Structure
Atomic number (Z): - On the Symbol - On the Periodic Table
Mass number (A): - On the Symbol - On the Periodic Table20
Ca
40.08
Review: What is Z? What is A?
Determine the number of protons, neutrons, and electrons.
31
GaGallium
69.72
32
GeGermanium
72.61
Periodic Table: an Important Tool in Chemistry but no set rules for what is included and where
16
S 32.06
S16
32.06
How can we tell which is the atomic number and the mass number?
Atomic Mass Unit
AMU
The “amu” is defined as one twelfth of the mass of an atom of carbon-12 (with 6 protons and 6 neutrons) and has a value of 1.660538921×10−27 kg.
AMU = relative measurement and used for comparison
Organization of the Periodic TableColumns – Groups All the elements have similar chemical and physical
properties All will chemically react in a similar way Names of groups
Rows – Periods Elements have same number of energy levels
Isotopes
Isotopes - Discovery Education Video
Isotopes: Atoms of an element with different masses
Naturally occurring Some are stable and some are radioactive
(unstable) Isotopes of an element have the same number
of ___________ and a different number of ______________.
Identifying Isotopes Isotope Notation1.
2.
On the Periodic Table, the number with the Decimal point is:
Atoms of the Same Element
Atoms of the Same Element
Atoms of the Same Element
Atomic Mass
Weighted Average Mass of isotopes Based on the percentage of each isotope
present.
Grades are often computed using a weighted average. Suppose that homework counts 10%, quizzes 20%,
Labs 10% and tests 60%. If: homework grade is 92quiz grade is 68lab grade is 88 test grade is 81What’s the overall grade?
Practice Atomic Structure
Identify the number of proton, neutron, & electrons of an atom of a specific element
Rounding the atomic mass on the Periodic Table gives the mass of the most common isotope
Atomic Number & Isotopes Correct symbol: A & Z Complete the table Complete the questions.
Practice: Find the Average Atomic Mass
Nucleus of each atom is represented Graphic below #4 - explains #5-7
Isotopes: Atomic Number & Mass Number Determine based on the chart – not the PT 2 Isotope notations
Element – A (X-A) A
ZX
Find Average Atomic Mass
Atomic Number & Isotope
Isotopes: Atomic Number & Mass Number
Element Isotope Symbol
Atomic Number Z
Mass Number A
# of protons
# of neutrons
# of electrons
Atom: Scanning Tunneling Microscope
Development of the Modern Atomic Model
Here are several models of the atom as they were developed in history:
............ ......
................
Atomic investigation – Discovery Education Video
Bohr - Discovery Education Video
Quantum Model Electron Cloud model of
the atom
Representing atoms with the Bohr model
Representing atoms with the Bohr Model
Bohr Model – Simplified but Useful ModelGroup
1Group
2Groups
2-12Group
13Group
14Group
15Group
16Group
17Group
18
P1
P2
P3
Bohr Model & the Periodic Table Making Conclusions
Compare and Contrast Why are elements placed in a group (column)? Why are elements placed in a period (row?)
Changing An Atom
Changing an Atom
Ions Atoms can lose or gain electrons when bonding to
make ionic compounds We keep track of the number of electrons that can be
lost or gained with oxidation numbers (also known as charges)
Ions are charged particles –when an atom has too many or too few electrons to be neutral No change to the nucleus Proton and neutrons stay the same number.
Ions – Charged Particles
7. When atoms of elements form ions (__________ __________, they must either __________ or _______ valence electrons.
Gain/lose? Charge Ion type?
Metals
Non-metals
Why are ions important? The ___________________ charged particles
are like a magnet.
Therefore, they are strongly held together in an ______________ _____________ forming an _____ ________________.
Representing atoms with the Bohr Model
IonsLithium atom - Lithium ion Ion Symbol
p+ p+
nº nº
e- e-
Fluorine atom Fluorine ion
p+ p+
nº nº
e- e-
Ions and ChargeNet electric charge
Note change
8
Ions and Charges for Representative Elements (Oxidation number keep track of electrons)
Group1
Group 2
Group 13
Group14
Group15
Group 16
Group 17
Group 18
Ion Making
Holy Molee Song
Making an ion of analkali metal, First column in the periodic chart,Leaves all the ions with a plus one chargeAnd they’re all a whole lot smallerthan they were before.
Second column over,Alkaline earths,Loses 2 electrons easily,So their ions all have a plus 2 charge, And they’re smaller than their neighbors to the left.
Next door, aluminum,the 3rd step overhas 3 electronsIt’d like to have removed.When they are gone, it has a +3 charge,And, by gosh!, It’s evensmaller than the “lefter” two.
But add one electron To the halogen group,So they all have a Negative one charge.They get 8x bigger thanThey were before.Puffed up, very large.
Sulfur and oxygenneed 2 electrons to give each a full andcomplete electron shell.Thus, minus 2 is their ionic charge.And they’re a little largerThan the “Hal-ions”.
Add three electrons to the nitrogen group.So that group has a triple minus charge.And the pattern we see makes it very clear.Negative ions are large!
Mole Resources for students http://molechemistry.info/
Nuclear Chemistry
Neutron to Proton Ratio
Types of Radiation
Alpha Decay
Beta decay
Gamma Decay
Radiation Strength
Nuclear Equations1. 1
1H + 94Be ---> 6
3Li + ?
2. 2713Al + 4
2He ---> 3015P + ?
3. 2412Mg 24
12Mg + ?
4. 23892U 234
90Th + ?
5. 146C 0
-1e + ?
6. 23994Pu + 4
2He 24296Cm + ?
Nuclear Equations Practice Website
Half-life Measure of Radioactive decay rate. Measured as the time it takes for ½ of a
sample of radioisotope’s nuclei to decay into its products.
Half LifeDecay of a radioisotope
Number of Half-Lives
Elapsed time Amount remaining
0 0 100 g
1 1.5 year 50 g
2 3 years 25 g
3 4.5 years 12.5 g
Half Life Problems How much of a 100g sample of an unstable
isotope remains after 25 years if the half life is 5 years?
3.1 g
Half Life Problems How much of a 60g sample of an unstable
isotope remains after 2 days if the half life is 12 hours?
7.5 g
Half Life Problems How much of a 20 g sample of an unstable
isotope remains after 6 sec if the half life is 0.5?
0.005 g
Atomic Nucleus (also known as nuclide)
Mass
Energy
Volume
Radioactive IsotopesA radioactive isotope has an unstable nucleus
that undergoes spontaneous changes. - Emits particles and energy
- Transmutates into another element
Particles emitted from a radioactive isotope
Type Symbol Charge Mass
Nuclear reactionsTotal number of atomic numbers and the total
mass numbers must be equal on both sides of the equation.
Examples:
Radioactive decay
No 2 radioactive isotopes decay at the same rate. Therefore, decay rate can be used to identify the isotope. Decay is measured by half life.
Fission and Fusion
Origins of Element
Got Calcium Where are most elements created? When was H and He created? What elements are made by small stars? What additional elements are made by large
stars? What elements are made by supernovae (large
exploding stars)?
Teachers' Domain: The Origin of the Elements
Teachers' Domain: The Elements: Forged in Stars