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