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. 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 notes Essential questions: What are the characteristics of an atom? In your notes: address both individual atoms and atoms of an element

Modern Atomic Theory All matter: Atoms of a given element: Atoms cannot be created nor destroyed in: In chemical reactions, atoms are

Atomic Theory (cont.) 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):

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): 20 Ca 40.08

31 Ga 69.72 32 Ge 72.61 Gallium Germanium Review: What is Z? What is A? Determine the number of protons, neutrons, and electrons. 31 Ga Gallium 69.72 32 Ge Germanium 72.61

Periodic Table: an Important Tool in Chemistry but no set rules for what is included and where 16 S 32.06 S 16 32.06 How can we tell which is the atomic number and the mass number?

AMU = relative measurement and used for comparison 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.

Organization of the Periodic Table Columns – 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 Notation 1. 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 92 quiz grade is 68 lab grade is 88 test grade is 81 What’s the overall grade?

Practice Atomic Structure Atomic Number & Isotopes 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 A # of protons # of neutrons # of electrons

Stable Isotopes - frequency http://www.muhlenberg.edu/depts/chemistry/pertable/PTFRAME.HTM

Atom: Scanning Tunneling Microscope

Development of the Modern Atomic Model Here are several models of the atom as they were developed in history: ............ ...... ................ Development of the Modern Atomic Model

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 Model Group 1 2 Groups 2-12 13 14 15 16 17 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 46 46

Why are ions important? The ___________________ charged particles are like a magnet. Therefore, they are strongly held together in an ______________ _____________ forming an _____ ________________. 47

Representing atoms with the Bohr Model

Ions Lithium atom - Lithium ion Ion Symbol p+ p+ nº nº e- e- Fluorine atom Fluorine ion 49 49

Ions and Charge Net electric charge Note change 8 50 50

Ions and Charges for Representative Elements (Oxidation number keep track of electrons) Group 1 2 13 14 15 16 17 Group 18 51

Ion Making Holy Molee Song 52 52

Making an ion of an alkali metal, First column in the periodic chart, Leaves all the ions with a plus one charge And they’re all a whole lot smaller than they were before. 53 53

Loses 2 electrons easily, So their ions all have a plus 2 charge, 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. 54 54

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It’d like to have removed. When they are gone, it has a +3 charge, Next door, aluminum, the 3rd step over has 3 electrons It’d like to have removed. When they are gone, it has a +3 charge, And, by gosh!, It’s even smaller than the “lefter” two. 56 56

But add one electron To the halogen group, So they all have a Negative one charge. They get 8x bigger than They were before. Puffed up, very large. 57 57

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complete electron shell. Thus, minus 2 is their ionic charge. Sulfur and oxygen need 2 electrons to give each a full and complete electron shell. Thus, minus 2 is their ionic charge. And they’re a little larger Than the “Hal-ions”. 59 59

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! 60 60

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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 Equations Practice Website 11H + 94Be ---> 63Li + ? 2713Al + 42He ---> 3015P + ? 2412Mg  2412Mg + ? 23892U  23490Th + ? 146C  0-1e + ? 23994Pu + 42He  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 Life Decay of a radioisotope Number of Half-Lives Elapsed time Amount remaining 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 Isotopes A 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 reactions Total 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