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Chemistry Monday, September 25th – Tuesday,
September 26th, 2017
Do-Now Title: “Nuclear Notation Review” 1. Answer the do-now questions on your
worksheet
2. Do not begin working on the other questions until instructed to do so
Finished? Take out your planner and table of
contents.
Announcements • ToCmustbeturnedinbyFriday• Recall
– TobeexemptfromsemesterfinalyoucannotmissmorethanfourTOTALstampsfromourToC’s
– Youalsoneeda70%+onunittestsandnomissinglabs/quizzes
• Retakeoldquizzesandtrade-indojopoints
• BacktoschoolnightThursday• MinimumdayFriday
Planner: • Last day for stamps: Thursday • ToC due by Friday (turn in to HW box) • Read Ch. 19 (all) • Retake Ch. 3 Quiz Table of Contents #1:
24. Nuclear Notation Review 25. Ch. 19 CN Part A
Review
CW 1. Take 10-15 minutes to complete the
review WS in your groups – Mass number for Br is 80, and the mass
number for Pb is 212
2. When finished, start reading Ch. 19
3. We will begin our notes shortly
FLT • I will be able to describe the three main
types of nuclear radiation by completing Ch. 19 CN A
Standard HS-PS1-8:Developmodelstoillustratethechangesinthecomposi;onofthenucleusoftheatomandtheenergyreleasedduringtheprocessesoffission,fusion,andradioac;vedecay
Ch. 19 Part A: Radiation • Title your notes & add assignment # • Complete Cornell-style • Copy down all bolded ideas • Noise level 0 • Raise hand to question/comment • Be prepared to pair-share-respond
Ch. 19 Part A: Radiation
Guiding Questions • Whatarethetwonuclearforces?• Whatarethethreetypesofradioac;vedecay?
• Whichisthedeadliesttypeofradioac;vedecay?
• HowdoyouprotectyourselffromAlpharadia;on?
Review–AtomicModels
Nucleons and Nuclear Forces
SubatomicPar;cles• In1932,JamesChadwickdiscoveredtheneutron
• Thiswasimportantinimprovingtheproton-electronatomicmodel
• Newmodel:Theproton-neutronnucleus
Proton-NeutronModel
SubatomicPar;cles• Wenowhavethreesubatomicpar;cles:– Protonsp+– Electronse-– Neutronsn0
• Nucleons=subatomicparNcleslocatedinthenucleusofatoms(p+andn0)– Nucleonsarecomposedofsmallerpar;clescalledquarks
Forces• Therearetwomainforcesatplayinournucleus:
– Electromagne;cforce(proton-protonrepulsion)– Strongforce(nucleonss;cktogether)
Forces• Notallnucleiarestable
– Posi;vely-chargedprotonscanrepeleachother• StrongNuclearForce=bindsp+andn0togetherinthenucleus
Unstable Nuclei – Strongforce=holdsnucleitogetherovershortdistances
– Largernucleicanbemoreunstable
Nuclear Stability
NuclearStability• StrongNuclearForce
– Thisforcecanonlyactoververyshortdistances– ItisthestrongestaXrac;veforce(137;mesmorethanelectromagne;c)
– Overextremelyshortdistances,thestrongnuclearforceoverridestherepulsionoftheelectromagne;cforce
• Lookingatthera;oofprotonstoneutronscanhelpusdeterminethestabilityofthenucleus
Band of Stability
• The region on a graph which indicates all stable nuclei when the number of neutrons are compared to the number of protons for all stable nuclei
NuclearStability• Largernuclidestendtobemoreunstable
– Allnuclideswithmorethan83protons(bismuth)areunstable
• Mostnuclideswanta1:1ofneutrons:protons– Heaviernuclidesneedmoreneutrons
Pair-Share-Respond 1. What are nucleons? 2. What force holds nucleons together? 3. What types of nuclei tend to be
unstable?
Radioactivity
Radioactivity
• Howdoesanunstablenucleusreleaseenergy?
Context • MarieCurie(1867-1934)helpeddiscovernewelements(PoloniumandRadium),aswellasradioac;veelements
• Curiestudiedmaterialsthatgaveoffrays,whichshecalledradioac;vity
Radiation • Radia;on=Rays∥clesemiXedbyaradioac;vesource
Radiation Radioisotopes=unstableisotopeswhosenucleiundergochangestobecomemorestable
Radioactivity
– Anunstablenucleus“decays”intoanewnucleusbychangingitsnumberofprotonsspontaneously
– Ifthenumberofprotonschanges,isitthesameelementanymore?
Radioactivity – RadioacNvedecay=unstablenucleusreleasesenergy/emitsradiaNon
Types of Radiation
Types of Radiation
What are the three main types of nuclear radiation?
Main Types of Radiation
1. Alpha (α) Radiation 2. Beta (β) Radiation 3. Gamma (Υ) Radiation
Alpha Radiation Alpha radiation = Emits alpha particles (helium) • Mass number decreases by 4, atomic number
decreases by 2
Alpha Radiation Ex/
Beta Radiation
• Beta Radiation = Emits a beta particle (electron) – Mass number stays the same. Atomic number increases by
1.
Beta Radiation Ex/
Gamma Radiation
• Gamma radiation = Emits a high-E photon(gamma ray).
• Tends to accompany other nuclear decay processes
Types of Radiation
• AlphaparNclesaretheleastpenetraNng.GammaraysarethemostpenetraNng.
Figure4.2:Thepenetra;ngpowerofradia;on.
© 2003 John Wiley and Sons Publishers
Arethereothertypesofdecay?
α-par;cleproduc;on
Spontaneousfission
β-par;cleproduc;on
Positronproduc;on
γ-rayproduc;on
Positron Production
• Positron = positively charged anti-electron
Review 1. Certain elements are radioactive because their atoms have
a. more neutrons than electrons. b. an unstable nucleus. c. a large nucleus. d. more neutrons than protons.
Review 2. An unstable nucleus releases energy by
a. emitting radiation. b. thermal vibrations. c. a chemical reaction. d. giving off heat.
Review 3. Which property does NOT describe an alpha particle?
a. 2+ charge b. a relatively large mass c. a negative charge d. low penetrating power
Review
4. When a radioactive nucleus releases a high-speed electron, the process can be described as
a. oxidation. b. alpha emission. c. beta emission. d. gamma radiation.
Pair-Share-Respond 1. Whatareradioisotopes?2. Whatareourthreemaintypesof
radia;on?3. Whichtypeisthemostdangerous?4. WhatisemiXedinbetadecay?5. WhatisemiXedinalphadecay?
CW 1. Underneath your notes, complete
the questions from page 694: – #1-5, 8, 9, 11
2. Finished? Read Ch. 19 Carefully
Chemistry Wednesday, September 27th – Thursday,
September 28th, 2017
Do-Now Title: “Video Notes: Nuclear Processes” 1. Write down today’s FLT. 2. When can you retake quizzes? 3. What can you trade in your dojo points for? List
specific examples with how many points they cost 4. Why do some nuclei undergo decay? 5. Identify the three main types of decay, and list
them in order from least penetrating to most penetrating
6. Use a pro-talk sentence frame to make a claim about nuclei, radiation, or decay.
7. Write “Video Notes” underneath your do-now Finished? Take out your planner and table of
contents.
Announcements • ToCdue• Finishretakes• AYendtutoringasneeded• Musthavecalculatorsnextweek
• Unittest– MulNplechoicesecNonandresponsesecNon
Planner: • Turn in ToC • Study for Unit Test (Ch. 1, 3, 13, 19) • Bring calculators next week Table of Contents #2:
1. Video Notes: Nuclear Processes
Video Notes • Let’sreviewsomeoftheconceptswecovered,aswellaslookatsometopicswewillbecoveringsoon
Video Notes 1. Whatarethefourfundamental
forces?2. Dis;nguishbetweennuclearfusion
andfission.3. Anatomicbombuseswhichof
theseprocesses?4. Whyisradioac;vedecayusefulto
uswhenstudyinghistory?5. Oneaddi;onalfact
Video Notes 1. Whatarethefourfundamental
forces?2. Dis;nguishbetweennuclearfusion
andfission.3. Anatomicbombuseswhichof
theseprocesses?4. Whyisradioac;vedecayusefulto
uswhenstudyinghistory?5. Oneaddi;onalfact
Introduction to Half-Life
Introduction to Half-Life • Unstablenucleidecay• Dotheyalldecayatthesamerate?
Introduction to Half-Life • Thehalf-lifeofanuclideistheNmeittakesfor½ofthesampletodecay
• A^ereachhalf-life,halfoftheremainingatomshavedecayed
intoanewelement
• Wecanrepresentthisgraphically– Whatwouldthatlooklike?
Introduction to Half-Life
Mini-Lab
Ch 19 Radioactive Half-Life Lab • Youwillusem&m’sorskiXlestorepresentisotopes– Whatareisotopes?
• Youmustplacepapertowelsoveryoursta;on/table– Pleasedonoteatwhileperformingthelab
– Contaminatedcandiesshouldbethrownoutattheend
– Tablesmustbewipeddownattheendforsanita;onpurposes
Ch 19 Radioactive Half-Life Lab • WriteyourstarNngnumberofcandies
– Youwillneedtocountout100candieswithoutcontaminaNon
• Usetwocupstoshakeyourcandies
• Pourthemoutacrossthepapertowels
Ch 19 Radioactive Half-Life Lab • Candiesfacingup=remainingisotopesàkeeptheseforthenextround
– Recordtheremainingnumberin
yourdatatable
• Candiesfacingdown=decayedisotopesàsettheseaside,astheywillnotbeusedanymore
Ch 19 Radioactive Half-Life Lab • Gatherupyourremainingcandiesandshakethemup.RepeatthestepsunNlallisotopeshave“Decayed”.
Time Classdata
1millionyears
2millionyears
3millionyears
4millionyears
5millionyears
6millionyears
7millionyears
8millionyears
9millionyears
10millionyears
11millionyears
12millionyears
Ch 19 Radioactive Half-Life Lab • Graphyourresultsonthebackofthepage.Don’tforgettolabelyouraxes.
• Alsographtheclassaveragedatausingadifferentcolorpen.
– Youshouldlabeleachorhaveakey• UsetheclassaveragegraphtoanswerthequesNonsbelow.
CW • TurninlabswhenfinishedJ
– Didyouanswerincompletesentences?
• StudyCh.19– Testnextweek!
• TurninToCifit’sready
Chemistry Friday, September 29th – Monday, October
2nd, 2017
Planner: • Finish WS + Study for Ch. 19 Quiz • Unit Test (Ch. 1, 3, 13, 19) 10/9-10/10 • Next lesson: calculators Table of Contents #2:
2. Return of the Brainstorm 3. Ch. 19 CN B 4. Nuclear Radiation WS
Announcements • Classdojoadjustment:
– 5points:pen,pencil,snack(limitoneperday)– 10points:newreferencesheet– 15points:stamp
• Unittest– Tues/Wed
• FinishCh.19– Thurs/Fri
• Ch.19Quiz+UnitReview– Mon/Tues
• UnitTest
Announcements • AnoteontheToC
– ToC’swithallstamps=+5dojopoints
– Missingstampsaretotaledattheendofeachsemestertohelpdeterminewhoisexemptfromthefinalornot
– Unstampedassignmentscanbeturnedinwithan“Incompleteassignment”formwiththeToCforparNalcreditàstapleeverythingtogether
FLT • I will be able to write balanced nuclear
equations by completing Ch. 19 Notes B
Standard HS-PS1-8:Developmodelstoillustratethechangesinthecomposi;onofthenucleusoftheatomandtheenergyreleasedduringtheprocessesoffission,fusion,andradioac;vedecay
Notes Protocol • Title your notes & add assignment # • Complete Cornell-style • Copy down all bolded ideas • Noise level 0 • Raise hand to question/comment • Be prepared to pair-share-respond
Ch. 19 CN B: Nuclear Transformation
Guiding Questions • What is nuclear fusion? • What is nuclear fission? • How do we write and balance
nuclear equations?
Recall
Radiation • When a nucleus spontaneously breaks down by
emitting radiation, the process is called radioactive decay.
Alpha Emission • Emits alpha particles, which contain two protons
and two neutrons and has a double positive charge.
• Alpha emitters are radioisotopes that decay by emitting alpha particles
αpar;cle=4He
2
Beta Emission • Emit beta particles • The neutron breaks apart into a proton, which
remains in the nucleus, and a fast-moving electron, which is released. This increases the atomic number by one.
β-par;cle=0e-1
Gamma Emission • Nuclei often emit gamma rays along with alpha
or beta particles during radioactive decay.
Nuclear Equations
Nuclear Equations • Radioactive decay can be shown in a nuclear
equation using the symbols for the original radioactive nucleus, the new nucleus, and the radiation emitted.
• Nuclear Equations à Balanced when both sides are equal to each other
• Radioactive nucleus à new nucleus + radiation
Nuclear Equations • In nuclear reactions, atoms transmutate • Transmutation = Conversion of an atom of
one element into an atom of another element
• Transmutation can occur by radioactive decay or when bombarded by other particles
CopyThisExample:
BALANCINGNUCLEAREQUATIONS1. Sumofmassnumbersmustbe=oneachside(le^
superscripts)
2. Sumsofatomicnumbers/charges(le^subscripts)oneachsideoftheequaNonmustbe=.
Examples:238U 4He+234Th92 290
214Pb 0β + 214Bi82 -183
Trythese:
CompletethenuclearequaNonsandstatethetypeofdecay:
1.217At213Bi+?
2.231Th0β+?
-1
3.208Tl 0e+?
-1
85 83
4He2
90231Pa91
208Pb8281
Fission & Fusion
Nuclear Fission • When the nuclei of certain isotopes are
bombarded with neutrons, they undergo fission • Fission = the splitting of a nucleus into
smaller fragments/nuclei.
Nuclear Fission • Chain reaction = Fission produces neutrons,
causing other atoms to undergo fissions, which in turn releases more neutrons, etc.
Nuclear Fusion • The energy released by the sun results from
nuclear fusion. • Fusion = when nuclei combine to produce a
nucleus of greater mass.
Nuclear Fusion • Fusion reactions, in which small nuclei combine,
release much more energy than fission reactions, in which large nuclei split.
Pair-Share-Respond 1. What is a transmutation?2. Distinguish between nuclear fission and
nuclear fusion.3. Which type releases more energy?
4. Complete the balanced equation:
Reminderfortoday’sWS
α-par;cleproduc;on
Spontaneousfission
β-par;cleproduc;on
Positronproduc;on
γ-rayproduc;on
FYI:ElectronCapturevs.BetaDecay
CW • Complete the WS
– Use periodic table – If written in isotope notation (example:
Carbon-14 or C-14) change to shorthand notation first
– Study by reading notes, the textbook, or quizzing your group members