SOL PS.2 THE NATURE OF MATTER • Matterisanythingthathasmassandoccupiesspace.

§ Allmatterismadeupofsmallparticlescalledatoms.§ Mattercanexistasasolid,aliquid,agas,orplasma.• Mattercanbeclassifiedaselements,compounds,andmixtures.

§ Theatomsofanyelementarealikebutaredifferentfromatomsofotherelements.§ Compoundsconsistoftwoormoreelementsthatarechemicallycombinedinafixed

ratio.§ Mixturesalsoconsistoftwoormoresubstances,butthesubstancesarenot

chemicallycombined.• Compoundscanbeclassifiedinseveralways,including:-acids,bases,salts-inorganic

andorganiccompounds.Acids• Acidsmakeupanimportantgroupofcompoundsthat

containhydrogenions.§ Whenacidsdissolveinwater,hydrogenions(H+)are

releasedintotheresultingsolution.§ Abaseisasubstancethatreleaseshydroxideions

(OH–)intosolution.§ pHisameasureofthehydrogenionconcentrationin

asolution.§ ThepHscalerangesfrom0–14.

§ SolutionswithapHlowerthan7areacidic;§ solutionswithapHgreaterthan7arebasic.§ ApHof7isneutral.

§ Whenanacidreactswithabase,asaltisformed,alongwithwater.

PhysicalProperties• Mattercanbedescribedbyitsphysicalproperties,whichinclude

§ shape§ density§ solubility

§ odor§ meltingpoint§ boilingpoint

§ color

• Somephysicalproperties,suchasdensity,boilingpoint,andsolubility,arecharacteristic

ofaspecificsubstanceanddonotdependonthesizeofthesample.• Characteristicpropertiescanbeusedtoidentifyunknownsubstances.• Equalvolumesofdifferentsubstancesusuallyhavedifferentmasses.

ChemicalProperties• Mattercanalsobedescribedbyitschemicalproperties,whichinclude

§ acidity§ basicity§ combustibility(howeasilyitcatchesfire)§ reactivity

• Achemicalpropertyindicateswhetherasubstancecanundergoachemicalchange.

SOLPS.3HISTORICALMODELSOFATOMICSTRUCTURE

AtomicStructure• Theatomisthebasicbuildingblockofmatterandconsistsof

subatomicparticles(proton,neutron,electron,andquark)thatdifferintheirlocation,charge,andrelativemass.

• Protonsandneutronsaremadeupofsmallerparticlescalledquarks.

• Sizeattheatomiclevelismeasuredonthenanoscale

ScientificContributions• Twomodelscommonlyusedare

theBohrandthe“electroncloud”(QuantumMechanics)models.

• TheBohrmodeldoesnotdepictthethree-dimensionalaspectofanatom,anditimpliesthatelectronsareinstaticorbits.

• The“electroncloud”modelbetterrepresentsourcurrentunderstandingofthestructureoftheatom.

SolidSphere

SOLPS.4THEPERIODICTABLE

Elements• Therearemorethan110knownelements.

§ Noelementwithanatomicnumbergreaterthan92isfoundnaturallyinmeasurablequantitiesonEarth.

§ Theremainingelementsareartificiallyproducedinalaboratorysetting.

§ ElementscombineinmanywaystoproducecompoundsthatmakeupallothersubstancesonEarth.

PeriodicTable• Theperiodictableofelementsisatoolusedtoorganizeinformationabouttheelements.

§ Eachboxintheperiodictablecontainsinformationaboutthestructureofanelement.

§ Anatom’sidentityisdirectlyrelatedtothenumberofprotonsin itsnucleus.

§ Thisisthebasisforthearrangementofatomsontheperiodictableofelements.

• Theverticalcolumnsinthetablearecalledgroupsorfamilies.

§ Elementsinthesamecolumn(family)oftheperiodictablecontainthesamenumberofelectronsintheirouterenergylevels.

§ Thisgivesrisetotheirsimilarpropertiesandisthebasisofperiodicity—therepetitivepatternofpropertiessuchasboilingpointacrossperiodsonthetable.

• Thehorizontalrowsarecalledperiods.§ Theperiodictableofelementsisanarrangementofelementsaccordingtoatomic

numberandproperties.§ Theinformationcanbeusedtopredictchemicalreactivity.§ Theboxesforalloftheelementsarearrangedinincreasingorderofatomicnumber.

MetalsandNonmetals• Theelementshaveanincreasingnonmetalliccharacterasone

readsfromlefttorightacrossthetable.• Alongthestair-steplinearethemetalloids,whichhave

propertiesofbothmetalsandnonmetals.• Thenonmetalsarelocatedtotherightofthestair-steplineon

theperiodictable.• Metalstendtoloseelectronsinchemicalreactions,

formingpositiveions.• Nonmetalstendtogainelectronsinchemicalreactions,formingnegativeions.

ReactionsandChemicalBonding• Gainingorlosingelectronsmakesanatomanion.• Gainingorlosingneutronsmakesanatomanisotope.• However,gainingorlosingaprotonmakesanatomintoacompletelydifferentelement.• Atomsreacttoformchemicallystablesubstancesthatareheldtogetherbychemicalbondsandare

representedbychemicalformulas.• Tobecomechemicallystable,atomsgain,lose,orshareelectrons.• Compoundsareformedwhenelementsreactchemically.• Whenametallicelementreactswithanonmetallicelement,

theiratomsgainandloseelectronsrespectively,formingionicbonds.

• Generally,whentwononmetalsreact,atomsshareelectrons,formingcovalent(molecular)bonds.

SOL PS.5 CONSERVATION OF MATTER - PHYSICAL AND CHEMICAL CHANGES PhysicalandChemicalChanges• Mattercanundergophysicalandchemicalchanges.

§ Inphysicalchanges,thechemicalcompositionofthesubstancesdoesnotchange.§ Inchemicalchanges,differentsubstancesareformed.§ Chemicalchangesareoftenaffectedbythesurfacearea/volumeratioofthematerials

involvedinthechange.• TheLawofConservationofMatter(Mass)statesthatregardlessofhowsubstanceswithin

aclosedsystemarechanged,thetotalmassremainsthesame.• TheLawofConservationofEnergystatesthatenergycannotbecreatedordestroyedbut

onlychangedfromoneformtoanother.ChemicalEquations

• Achemicalequationrepresentsthechangesthattakeplaceinachemicalreaction.

§ Thechemicalformulasofthereactantsarewrittenontheleft,anarrowindicatesachangetonewsubstances,andthechemicalformulasoftheproductsarewrittenontheright.

§ Chemicalreactionsareclassifiedintotwobroadtypes:onesinwhichenergyisreleased(exothermic)andonesinwhichenergyisabsorbed(endothermic).

NuclearReactions• Anothertypeofchangeoccursinnuclearreactions.

§ Nuclearenergyistheenergystoredinthenucleusofanatom.

§ Thisenergycanbereleasedbyjoiningnucleitogether(fusion)orbysplittingnuclei

(fission),resultingintheconversionofminuteamountsofmatterintoenergy.§ Innuclearreactions,asmallamountofmatterproducesalargeamountofenergy.§ However,therearepotentialnegativeeffectsofusingnuclearenergy,

includingradioactivenuclearwastestorageanddisposal.

SOL PS.6 FORMS OF ENERGY Potential&KineticEnergy• Energyistheabilitytodowork.• Energyexistsintwostates.

§ Potentialenergyisstoredenergybasedonpositionorchemicalcomposition.Studentsshouldknowthattheamountofpotentialenergyassociatedwithanobjectdependsonitsposition.

§ Kineticenergyisenergyofmotion.Theamountofkineticenergydependsonthemassandvelocityofthemovingobject.

FormsofEnergy

• Importantformsofenergyincluderadiant,thermal,chemical,electrical,mechanical,and

nuclearenergy.• Visiblelightisaformofradiantenergyandsoundisaform

ofmechanicalenergy.• Energycanbetransformedfromonetypetoanother.• Inanyenergyconversion,someoftheenergyislosttothe

environmentasthermalenergy.

SOL PS.7 THERMAL ENERGY HeatandTemperature• Heatandtemperaturearenotthesamething.• Heatisthetransferofthermalenergybetweensubstancesofdifferenttemperature.

§ Asthermalenergyisadded,thetemperatureofasubstanceincreases.• Temperatureisameasureoftheaveragekineticenergyofthemoleculesofasubstance.

§ Increasedtemperaturemeansgreateraveragekineticenergyofthemoleculesinthesubstancebeingmeasured,andmostsubstancesexpandwhenheated.

§ Thetemperatureofabsolutezero(–273oC/0K)isthetheoreticalpointatwhichmolecularmotionstops.

• Atomsandmoleculesarecontinuouslyinmotion.

Conduction,Convection,Radiation

• Thetransferofthermalenergyoccursinthreeways:byconduction,byconvection,and

byradiation.

• Asthermalenergyisaddedtoortakenawayfromasystem,thetemperaturedoesnotalwayschange.

• Thereisnochangeintemperatureduringaphase

change(freezing,melting,condensing,evaporating,boiling,andvaporizing)asthisenergyisbeingusedtomakeorbreakbondsbetweenmolecules.

SOL PS.8 SOUND ENERGY SoundWaves• Soundisproducedbyvibrationsandisatypeofmechanicalenergy.• Soundneedsamedium(solid,liquid,orgas)inwhichtotravel.• Soundtravelsincompressionwavesandataspeedmuchslowerthanlight.• Inacompressionwave,mattervibratesinthesamedirectioninwhichthewavetravels.

• Allwavesexhibitcertaincharacteristics:wavelength,frequency,andamplitude.§ Aswavelengthincreases,frequencydecreases.§ Acompression(longitudinal)waveconsistsofa

repeatingpatternofcompressionsandrarefactions.

§ Wavelengthismeasuredasthedistancefromone

compressiontothenextcompressionorthedistancefromonerarefactiontothenextrarefaction.

• Soundtravelsataspeedmuchslowerthanlight.§ Thespeedofsounddependsontwothings:themediumthroughwhichthewaves

travelandthetemperatureofthemedium.

ResonanceandReflection• Resonanceisthetendencyofasystemtovibrate

atmaximumamplitudeatcertainfrequencies.

• Reflectionandinterferencepatternsareusedin

ultrasonictechnology,includingsonarandmedicaldiagnosis.

SOL PS.9 LIGHT ENERGY & TRANSVERSE WAVES TransverseWaves• Visiblelightisaformofradiantenergythatmoves

intransversewaves.• Alltransversewavesexhibitcertain

characteristics:wavelength,crest,trough,frequency,andamplitude.§ Aswavelengthincreases,frequencydecreases.§ Thereisaninverse

relationshipbetweenfrequencyandwavelength.• Radiantenergytravelsinstraightlinesuntilitstrikesanobjectwhereitcanbereflected,

absorbed,ortransmitted.

ElectromagneticSpectrum

• Electromagneticwavesarearrangedontheelectromagneticspectrumbywavelength.• Alltypesofelectromagneticradiationtravelatthespeedoflight,butdifferinwavelength.• Theelectromagneticspectrumincludesgammarays,X-rays,ultraviolet,visiblelight,

infrared,radioandmicrowaves.§ Radiowavesarethelowestenergywavesandhavethelongestwavelengthand

thelowestfrequency.§ Gammaraysarethehighestenergywavesandhavetheshortestwavelengthand

thehighestfrequency.§ Visiblelightliesinbetweenandmakesuponlyasmallportionoftheelectromagnetic

spectrum.

Reflection,Refraction,Diffraction• Asvisiblelighttravelsthroughdifferentmedia,itundergoesachangeinspeedthatmay

resultinrefraction.• Plane,concave,andconvexmirrorsallreflectlight.

§ Convexmirrorsdivergelightandproduceasmaller,uprightimage.

§ Concavemirrorsconvergelightandproduceanupright,magnifiedimageifcloseandaninverted,smallerimageiffaraway.

• Concaveandconvexlensesrefractlight.§ Convexlensesconvergelight.§ Concavelensesdivergelight.

SOLPS.10WORK,FORCE,&MOTIONSpeed,Velocity,andAcceleration• Accelerationisthechangeinvelocityperunitoftime.

§ Anobjectmovingwithconstantvelocityhasnoacceleration.

§ Adecreaseinvelocityisnegativeaccelerationordeceleration.

§ Adistance-timegraphforaccelerationisalwaysacurve.§ Objectsmovingwithcircularmotionareconstantly

acceleratingbecausedirection(andhencevelocity)isconstantlychanging.

• Speedisthechangeinpositionofanobjectperunitoftime.• Velocitymayhaveapositiveoranegativevaluedependingonthedirectionofthechangeinposition,

whereasspeedalwayshasapositivevalueandisnon-directional.

Newton'sLaws• Newton’sthreelawsofmotiondescribethemotionofallcommonobjects. • Massandweightarenotequivalent.

§ Massistheamountofmatterinagivensubstance.§ Weightisameasureoftheforceduetogravityactingonamass.§ Weightismeasuredinnewtons.

• Aforceisapushorpull.§ Forceismeasuredinnewtons.§ Forcecancauseobjectstomove,stopmoving,changespeed,orchangedirection.

• Workisdonewhenanobjectismovedthroughadistanceinthedirectionoftheappliedforce.

• Asimplemachineisadevicethatmakesworkeasier.§ Simplemachineshavedifferentpurposes:

§ tochangetheeffortneeded(mechanicaladvantage),

§ tochangethedirectionordistancethroughwhichtheforceisapplied,

§ tochangethespeedatwhichtheresistancemoves,

§ oracombinationofthese.

• Duetofriction,theworkputintoamachineisalwaysgreaterthantheworkoutput.§ Theratioofworkoutputtoworkinputis

calledefficiency.

• Mathematicalformulasareusedtocalculatespeed,force,work,andpower.§ Speed=distance/time(s=d/t)§ Force=mass×acceleration(F=ma)§ Work=force×distance(W=Fd)§ Power=work/time(P=W/t).

SOL PS.11 ELECTRICITY AND MAGNETISM Staticelectricity,Currentelectricity,andCircuits• Severalfactorsaffecthowmuchelectricitycanflowthroughasystem.• Resistanceisapropertyofmatterthataffectstheflowofelectricity.Somesubstanceshave

moreresistancethanothers.• Frictioncancauseelectronstobetransferredfromoneobjecttoanother.

§ Thesestaticelectricalchargescanbuilduponanobjectandbedischargedslowlyorrapidly.

§ Thisisoftencalledstaticelectricity.

Electromagnets,MotorsandGeneratorsandtheiruses• Electricityisrelatedtomagnetism.• Magneticfieldscanproduceelectricalcurrentinconductors.

§ Electricitycanproduceamagneticfieldandcauseironandsteelobjectstoactlikemagnets.

§ Electromagnetsaretemporarymagnetsthatlosetheirmagnetismwhentheelectriccurrentisremoved.

• Bothamotorandageneratorhavemagnets(orelectromagnets)andacoilofwirethatcreatesanothermagneticfield.§ Ageneratorisadevicethat

convertsmechanicalenergyintoelectricalenergy.

§ Mostoftheelectricalenergyweusecomesfromgenerators.

§ Electricmotorsconvertelectricalenergyintomechanicalenergythatisusedtodowork.

§ Examplesofmotorsincludethoseinmanyhouseholdappliances,suchasblendersandwashingmachines.

Conductors,Semiconductors,Insulators• Aconductorisamaterialthattransfersanelectriccurrentwell.• Aninsulatorismaterialthatdoesnottransferanelectriccurrent.• Asemiconductorisin-betweenaconductorandaninsulator.• Thediodeisasemiconductordevicethatactslikeaonewayvalvetocontroltheflowof

electricityinelectricalcircuits.§ Solarcellsaremadeofsemiconductordiodes

thatproducedirectcurrent(DC)whenvisiblelight,infraredlight(IR),orultraviolet(UV)energystrikesthem.

§ Lightemittingdiodes(LED)emitvisiblelightorinfraredradiationwhencurrentpassesthroughthem.

§ AnexampleisthetransmitterinaninfraredTVremoteorthelightingcoursebehindthescreeninanLEDTVornotebookcomputerscreen.

• Transistorsaresemiconductordevicesmadefromsilicon,andothersemiconductors.§ Theyareusedtoamplifyelectricalsignals(instereos,radios,etc.)ortoactlikealight

switchturningtheflowofelectricityonandoff