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Atom Structure
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PURE SUBSTANCESELEMENTSCOMPOUNDS92
1-92NATURALMAN MADE25
93-118118products of artificial nuclear reactionsfound on earthsomeNATURALARTIFICIALCOMPOUNDSmajoritymillionsPlasticsCatalystsPigmentsFertilizersMedicineFibresPreservativesEtcUranium
HALF LIFEThe amount of time for a radioactive material to decay to 50% of its original massC14 decays to N14 with a half life of 5730 years
HALF LIVES
Ununoctium5 ms Radon3.823495 d Ununseptium50 ms Mendelevium51.5 d Ununhexium120 ms Fermium100.5 d Ununpentium1 m Einsteinium1.2922 y Ununquadium1.33 m Promethium17.73 y Darmstadtium4 m Actinium21.7865 y Roentgenium10 m Polonium102.1 y Ununtrium20 m Californium900.6 y Francium21.7 m Berkelium1379 y Meitnerium30 m Radium1.59103 y Ununbium40 m Americium7388 y Hassium1.11 h Protactinium32788 y Bohrium1.5 h Neptunium2.1455106 y Seaborgium1.94 h Technetium4.12106 y Nobelium2.78 h Curium1.56107 y Dubnium5.56 h Plutonium7.93107 y Astatine8.06 h Uranium4.471109 y Lawrencium10 h Thorium1.4061010 y Rutherfordium13.1 h Bismuth1.91019 y
Atomic Structure
The structure of the atom
The AtomNucleusElectronShell = Energy level
MOST COMMON ELEMENT IN UNIVERSE?
HydrogenProtonElectronHydrogen has one proton, one electron and NO neutrons75 % of the mass of the universe
WHERE ARE BIGGER ATOMS CREATED ?SUPERNOVA
ORGANIZATION OF ELECTRONSElectrons occupy closest shells first
Outer shells have more electrons and more energy 1st shell 2 electrons (VIP seating)2nd shell 8 electrons3rd shell 18 electrons4th shell 32 electrons
ATOMIC NUMBERThe number of protons in the nucleus
In a NEUTRAL atom there are an equal number of PROTONS & ELECTRONS
ATOMIC MASSThe sum of the protons and neutrons in the atom
Atoms sometimes have equal number of protons and neutron
e.g. C 6 protons, 6 neutrons
ATOMIC MASSBUT USUALLY PROTONS NOT = NEUTRONS
e.g. Co 27 protons, 32 neutrons
ATOMIC MASSELECTRONS - have a negligible weight compared to neutrons and protons so it is not included
PROTON = 1836 x mass of electron
ISOTOPEVariations of an atom with different number of NEUTRONS
IN NATURE12C 6 P, 6 N= 98.93 %13C 6 P, 7 N= 1.07 %14C 6 P, 8 N= 0.0000000001%
An atomic number is calculated by taking a weighted average of the isotopesx 0.9893= 11.8716x 0.0107= 0.1391x 0.000000000001= +0.00000000001412.0107
ISOTOPEISOTOPE = atoms with different numbers of NEUTRONS
atomic number = a weighted average of the isotopes
IN NATURE1H 1 P = 99.998 %2H1 P, 1 N= 0.0185%3H 1 P, 2 N= almost 0% (unstable)1 x 0.99980= 0.999802 x 0.000185 = 0.000373 x 0= +01.0015
IONSAn atom or molecule with more or less ELECTRONS
Normally in an atom there are an equal number of PROTONS & ELECTRONS= NEUTRAL
When there are more or less ELECTRONS ---> atoms have a CHARGE
ANIONA negative ion = more electrons
e.g. Cl - = 1 extra electron
CATIONA positive ion = less electrons
e.g.Na+ = 1 less electronCa+2= 2 less electrons
Mass and atomic number
ParticleRelative MassRelative ChargeProton11Neutron10Electron0-1
ATOM PROTONSNEUTRONSATOMIC MASSELECTRONSe- lost or gained11Na+11112210-1e-24Mg2+12O2-816Cl-1835238U092K1939-1 e-Rb+3786I-74127
TYPES OF ELECTRONSINTERNALEXTERNAL orVALENCE ELECTRONSCloser and have stronger attraction to nucleusAre the electrons responsible for chemical reactions
VALENCE ELECTRONSVALENCE ELECTRONSFurthest from the nucleus in the last shellEasiest ones to react with other atoms
RULE OF OCTETAtoms try to fill their valence shells with 8 electrons to become more stable
RULE OF DUPLETare exceptions to the rule of octet H, He, Li, Be, Boron
CHEMICAL BONDSatoms steal or share valence electrons from other atoms
Atoms that dont have 8 react with other atoms to get stable by:-stealing electrons from others-giving electrons to others-sharing electrons
ENERGY LEVELS
ElementSymbolAtomic numberElectronic configuration (or Electron arrangement) KLMN1st2nd3rd4th5th6th7thVALENCEshellshell shell shell shell shell shell(2)(8)(18)(32)(32)(18)(8)(8)HydrogenHeliumLithiumBerylliumBoronCarbonNitrogenOxygenFluorineNeonSodiumMagnesiumAluminiumSiliconPhosphorusSulphurChlorineArgonPotassiumCalcium
ElementSymbolAtomic numberElectronic configuration (or Electron arrangement) KLMN1st2nd3rd4th5th6th7thVALENCEshellshell shell shell shell shell shell(2)(8)(18)(32)(32)(18)(8)(8)HydrogenH111HeliumHe222LithiumLi3211BerylliumBe4222BoronB5233CarbonC6244NitrogenN7255OxygenO8266FluorineF9277NeonNe10288SodiumNa112811MagnesiumMg122822AluminiumAl132833SiliconSi142844PhosphorusP152855SulphurS162866ChlorineCl172877ArgonAr182888PotassiumK1928811CalciumCa2028822
HeliumElectronProtonNeutronHelium has two electrons, two protons and two neutrons
LithiumProtonsNeutronsElectrons
BerylliumProtonsNeutronsElectronsBeryllium has four electrons, four protons and five neutrons.
BoronProtonsNeutronsElectronsBoron has five electrons, five protons and six neutrons.
CarbonProtonsNeutronsElectronsCarbon has six electrons, six protons and six neutrons.
NitrogenProtonsNeutronsElectronsNitrogen has seven electrons, seven protons and seven neutrons.
OxygenProtonsNeutronsElectronsOxygen has eight electrons, eight protons and eight neutrons.
FluorineProtonsNeutronsElectronsFluorine has nine electrons, nine protons and ten neutrons.
NeonProtonsNeutronsElectronsNeon has ten electrons, ten protons and ten neutrons.
SodiumProtonsNeutronsElectronsSodium has eleven electrons, eleven protons and twelve neutrons.
DRAW ELECTRON CONFIGURATION
HLiAlMgArNeBeNBOHePK
LEWIS DOT STUCTUREValence electrons are represented by points
Li
Mg
He
Be
C
N
O
H
Ne
LEWIS DOT STRUCTURE
HLiSiAlMgNaArNeSBeNCaBOCHePClKF
LEWIS STUCTUREElements try to get stable 8 by:-sharing-stealing-giving
EXCEPTIONSHydrogenHelium
H O H
O C O
Na Cl
DIATOMIC ATOMSElements try to get stable 8 by:-sharing-stealing-giving
EXCEPTIONSHydrogenHelium
H H
O O
Cl Cl
N N
Br BrSome element exist in nature in pairsex. H2 or O2
LEWIS STUCTUREDraw in electrons in interaction
Write their formulas
H O H
O C O
Na Cl
DRAWCH4
CH3CH3
CLASSWORKCh 4-3 Atomic #, mass, isotopesP 98 101Questions # 11 -13
P101 #14 Table
Valence & Lewis DotP140 ,141 # 26,28
PERIODIC TABLE PROJECTPOSTER
Preferably find material made of that element
If material very difficult to find or radioactive or expensive use colourful picture
ELECTRON SHELLS
spdfg11223345746810135911141721612151822267161923273182024283236
AVOGADROS PRINCIPLE
PROPERTIES OF COMPOUNDSTYPEOFCOMPOUNDSTYPE OFBONDSGEOMETRICFORMATIONOFATOMS
Exceptions to the Octet RuleThere are three general ways in which the octet rule breaks down: 1. Molecules with an odd number of electrons 2. Molecules in which an atom has less than an octet 3. Molecules in which an atom has more than an octet
Odd number of electronsDraw the Lewis structure for the molecule nitrous oxide (NO):
1. Total electrons: 6+5=11
2. Bonding structure: 3. Octet on "outer" element: 4. Remainder of electrons (11-8 = 3) on "central" atom: 5. There are currently 5 valence electrons around the nitrogen. A double bond would place 7 around the nitrogen, and a triple bond would place 9 around the nitrogen.
We appear unable to get an octet around each atom
Less than an octet (most often encountered with elements of Boron and Beryllium)Draw the Lewis structure for boron trifluoride (BF3): 1. Add electrons (3*7) + 3 = 24