Today is Thursday, February 19 th , 2015 Pre-Class: Exactly how big is an atom, would you say? Of what is it made? Take a laminated periodic table, too! In This Lesson: Atomic Structure (Lesson 6 of 6) Stuff You Need : Worksheet Laminated Periodic Table
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Today is Thursday, February 19 th, 2015 Pre-Class: Exactly how big is an atom, would you say? Of what is it made? Take a laminated periodic table, too!
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Transcript
Today is Thursday,February 19th, 2015
Pre-Class:Exactly how big is an atom, would
you say?
Of what is it made?
Take a laminated periodic table, too!
In This Lesson:Atomic Structure
(Lesson 6 of 6)
Stuff You Need:WorksheetLaminated Periodic Table
Today’s Agenda
• This is a two day lesson!• Day 1:
– Atoms– Subatomic Particles– Notation– Ions
• Day 2:– Isotopes– Calculating atomic mass– Isotope Bean Lab
• Where is this in my book?– P. 101 and following…
By the end of this lesson…
• You should be able to describe the three main components of an atom and what happens when each of these components changes in number.
• You should be able to calculate atomic mass using a weighted average.
• Remember the Law of Conservation of Matter?• Here’s a weird thought…since atoms are never
destroyed or created (only “recycled”), the same atoms that were in stars at the beginning of time are partially in YOU right now!
• The same goes for our ancestors.– It’s estimated that around 1 billion of your many atoms
once belonged to Shakespeare. Some of the rest may have come from Henry VIII or Julius Caesar or anyone else that died quite a while ago.
• Also, one more thing – that means that most of the water you drink and in your body is recycled dinosaur urine. Yum!http://upload.wikimedia.org/wikipedia/commons/thumb/c/c3/NGC_4414_(NASA-med).jpg/300px-NGC_4414_(NASA-med).jpg
Atoms and Subatomic Particles
• Atoms are the smallest particle of an element that still behaves like that element.
• Generally, atoms are arranged such that there is a dense center core (the nucleus) surrounded by a diffuse field.
• In (almost) every atom, there are the following three key subatomic particles:– Proton– Neutron– Electron
Aside: Sub-subatomic Particles
• Below the level of protons, neutrons, and electrons are other subatomic particles.
• Without going into too much depth:– Protons are made of three quarks, two “up”
and one “down.”– Neutrons are made of three quarks, two
“down” and one “up.”– Electrons are made of…electrons.
• How many protons, electrons and neutrons are in the following atoms?
• 9Be– Protons = 4 Electrons = 4 Neutrons = 5
• 20Ne– Protons = 10 Electrons = 10 Neutrons = 10
• 35Cl–Protons = 17 Electrons = 17 Neutrons = 18
How Many p+, no, e-?
17
10
4
On your worksheets…
• Take 6.57 minutes and try #1-3 and 5.– For #1, leave out:
• Atomic Mass• Isotope• Isotope Name
– For #5, leave out:• Isotope Name
• NOTE: “Atomic mass/weight” and “atomic number” are different. DO NOT use atomic mass or atomic weight for now.
For a little practice…
• …we’re going to build some atoms with our computers using one of two methods:– PhET – Build an Atom– ExploreLearning – Element Builder
PhET
• Visit this website (listed in my Chem Links page):– http://phet.colorado.edu/en/simulation/build-an-
atom• Once here, click “Run Now.”• When the applet loads, hit the + signs on the right
side next to “Symbol,” “Mass Number,” and “Net Charge.”
• Then, start building atoms by clicking and dragging subatomic particles to the appropriate places.
Element Builder
• [Log-in Instructions]
Build Your Own Elements
• Build the following elements (don’t forget all the subatomic particles):– Hydrogen, Oxygen, Lithium, Carbon
• Questions to ponder:– What happens when you change the number of protons?– What happens when you change the number of neutrons?– What happens with you change the number of electrons?
Changing Protons
• Changing the number of protons changes the element.
• In other words, the atomic number of an element never changes.– It is always equal to the atomic number.
Changing Neutrons
• Changing the number of neutrons in an atom changes the mass number, creating a new isotope.
• Isotopes are atoms of the same element that have different atomic masses.– Example: Carbon always has 6 protons. Sometimes
it has 6 neutrons, sometimes it has 8 neutrons.– Thus, Carbon (mass 12) and Carbon (mass 14) are