Grade 12 Chemistry Notes on the Structure and Properties of Matter. Includes topics varying from the current model of the atom, light, the photoelectric electric effect, the atomic line spectra, wave particle duality, heisenberg's uncertainty principle, quantum numbers, electron configuration, hund...
History of theAtomicMotel
3I
Describethe contributions
of scientists to the currentmodelof theatom
understand specifically the contributions of Bohr in connectionto an understanding oflight
go t atoms
sulphur iron copperlead all matterismadeof
to I e r indivisible particlescalled
atoms
Atomsof anelementare
identical
Eachelementhasdifferent
atoms
Atoms ofdifferent elements
combine in constantratios
to form compounds
reactionsbut arenotcreated
nordestroyed
J J Thompson plumpuddingRaisinBun
mom Noindicationofexactly
Anelectrongoesfrom where the protonelectron
a cathode to an anode
Thebeam ofelectron
me
spacebetween two
oppositely chargedmetal
parallelplates
thetube is connected to an
electrical source
cathodeanode
o on
crescent
screen
tt
observation thecathoderay conclusion mattersis
A particles
produces a strongflorescence involved
or brightlightwhentheray
, strikes theseed
surface to the otherendof
thetube
observation thebeambent conclusion particleis
towards the positiveplate negativelycharted
Howdidherelateelectronstothe
atom
Heknewthatallmatterwas
madeupofatomsandthat
these tinyparticlesmusthave
comefromatoms
Hehadalsofoundthat
smallerthan thehydrogen
atomusingthe mass to
chargeratio
Rutherford Planetary Atomicnuclear t
Modelclan spex
mom
particles it wentthrough
iii
undeflected Fewscattered
mm itiii
no neutronscan't
acountformass
smallregionof theatom
the nucleus ispositively
particlesare positivelycharged
into andonly a fewfullydeflected
causingthemtocollapse
Mass oftheatomwasnot
equal to whatwasexpected mostparticles passedthrough
onedidnotaccountforneutrons soatomsaremostlyempty
T
e
somepositive a particles
deflected or bouncedback
Thus a nucleus is positive
protons andholdsmostof
, an atom'smass
Electrons areorbiting the
center of anatom farfrom
it at highspeed
Thecenterof theatom
holds the positiveparticles
theycannotbeuniformly
distributed
the positively chargedcenter
mustbeverysmall
Understand the connectionsbetween Bohr's model of theatom t his understanding of light
Bohr'sModel of theAtom
LIGHT behaves as a wave Behaves as a particle akaphoton
n im
Evidenced
by the PHOTOELECTRIC Effect
amountofe required toejecte
specific
Liz eyre ejects
off
jumps
mum
time
of wavesin unittimefrequency is neutral
negative
speed A x r
mis t
cos 3oxiosmis speedoflightin avacuum Iet Einstein
Photonstravelinpackagescalled quanta
Einsteinciaoscreatedthequantumtheoryoflightwhichstatesthat
Frequency is directly proportional to E electromagneticradiationtraveledas tinypacketsofenergycalledquanta
or photonsthatbehavedlikeparticlesratherthancontinuouswaves
oflightprovidesthefoundationforarevolute
Einstein'sworkonquanta
Photoelectriceffects
earlytacos
whenlightwasshoneon ametalelectronswereemittedfromthatmeta
Lightwasknowntobea formofenergycapableofknockingloseanelec
froma metal
Therefore lightcouldsupplyenoughenergy to ejectanelectro
EinsteinEXPLAININGPLANCK'sTHEORY
Theorizedthat electromagneticradiation had a dualwaveparticle
nature behaveslikea waveandparticles
Thinkoflightasparticlesthateachcarryonequantumofenergypno
photons a particleof electromagneticradiationhavingzeromassan
carrying a quantumofenergy
E nr
, conclusions
Electromagnetic radiation is absorbedby matter onlyin whole
number of photons
inorderfor an e to be ejected the e mustbestruckby
a singlephotonwithminimum frequency
Lightnotons
son
sodium
metal
mayyank119001 emitsin
ePackages
My
S 4498 called
aquatnta
mitter m
emit
colora
oooo
IIe emitcolorB
Quantumtheory
Planck suggested that energyinsteadof being givenoff in continuous waves is instead givenoff in little packets of
energyor quanta
oThewordquantum meansa fixedamount thinkofit as flashes ofenergy
Alsocalled a photonwhendescribing a quantum oflight
Planck'sideawasthat onequantum
ofenergyconephotonswas related to its frequency by the equation Epnoton hr
The constant h planck'sconstant has a value of 6.6262103 s s e is theenergyand v is the frequencyoftheradia
Anobjectcanonlygainor loseenergy byabsorbing or emittingradiantenergy in
Planck'shypothesis Quanta
Energy ofradiation is proportional isproportional to frequency Ehr
Note
oLongwavelength small frequency
Shortwavelengthnighfrequency 38
MaxPlanckstudied emission oflightfrom hot objects
observed color of lightvaried with temperature
suggested the objectsdonot continuouslyemit E butemit e in smallspecific amounts
oLightis absorbedor emittedin a little packetor bundle called a quantum quanta plural
Quantum minimumamountof E that canbe lost or gainedby an atom
Energiesare quantized thinkstepsnotaramp
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