3.1 Atomic StructurePages 70 - 76Pages 70 - 76

Goal 1Goal 1

Explain the historical Explain the historical progression of the atomic theoryprogression of the atomic theory

400 BC 400 BC DemocritusDemocritus

Greek Greek ““Happy philosopher”Happy philosopher”Geometry pioneerGeometry pioneerAstronomyAstronomy

Milky wayMilky way

Democritus’ atomic theoryDemocritus’ atomic theory

Real properties => perceived propertiesReal properties => perceived propertiesSolid objectsSolid objects

Pointy atomsPointy atomsHooks Hooks

Liquid substancesLiquid substancesRoundRoundSlipSlip

1808 1808 John DaltonJohn DaltonEnglandEnglandWorked at collegeWorked at collegeScientific researchScientific research

Numerical dataNumerical dataWidely acceptedWidely accepted

Dalton’s Atomic theoryDalton’s Atomic theory

1.1. Every element is made of tiny, unique Every element is made of tiny, unique particles called atoms that cannot be particles called atoms that cannot be subdividedsubdivided

2.2. Atoms of the same element are exactly alikeAtoms of the same element are exactly alike

3.3. Atoms of different elements can join to form Atoms of different elements can join to form moleculesmolecules

1903 1903 JJ ThomsonJJ ThomsonEnglandEnglandProfessor at Cambridge UniversityProfessor at Cambridge UniversityDiscovered electron Discovered electron Atoms are made up of smaller particlesAtoms are made up of smaller particles

““plum pudding” of + and – charged plum pudding” of + and – charged particles scattered in jelly-like substanceparticles scattered in jelly-like substance

1911 1911 Ernest RutherfordErnest RutherfordNew ZealandNew ZealandProfessor in England UniversitiesProfessor in England UniversitiesUsed alpha ray scattering and gold foilUsed alpha ray scattering and gold foil

Rutherford’s atomic model: Mini solar Rutherford’s atomic model: Mini solar systemsystemDense nucleiDense nucleiOrbiting electronsOrbiting electrons

1913 1913 Niels BohrNiels BohrDenmarkDenmarkCopenhagen Copenhagen

UniversityUniversityWorked withWorked with

RutherfordRutherfordBohrBohrPlanckPlanckEinsteinEinstein

Bohr’s Atomic ModelBohr’s Atomic ModelNucleus of heavy particlesNucleus of heavy particlesElectrons orbit on Electrons orbit on set pathsset pathsEach path has its own energy levelEach path has its own energy levelElectrons must gain or lose energy to switch Electrons must gain or lose energy to switch

pathspaths

Modern Atomic ModelModern Atomic Model

Nucleus of protons and neutronsNucleus of protons and neutronsElectrons behave like waves on a vibrating Electrons behave like waves on a vibrating

stringstringCannot determine Cannot determine exactexact location of electrons location of electronsElectrons found in orbitals of energy levelsElectrons found in orbitals of energy levelsValence electrons are outermost electronsValence electrons are outermost electrons

Goal 2Goal 2

Explain the charge, mass, and Explain the charge, mass, and location of each part of the atom location of each part of the atom according to the modern modelaccording to the modern model

ProtonProtonCharge Charge +1+1

Mass Mass 1.67 x 101.67 x 10-27-27 kg kg

Location Location nucleusnucleus

NeutronNeutronCharge Charge 00

Mass Mass 1.67 x 101.67 x 10-27-27 kg kg

Location Location nucleusnucleus

ElectronElectronCharge Charge -1-1

Mass Mass 9.11 x 109.11 x 10-31-31 kg kg

Location Location Orbitals around nucleusOrbitals around nucleus

ss orbital orbitalSphere shapeSphere shapeSurrounds nucleusSurrounds nucleusHolds max 2 electronsHolds max 2 electrons11stst energy level (lowest) energy level (lowest)

pp orbital orbitalDumbbell shapeDumbbell shape3 dimensional orientation3 dimensional orientationEach dumbbell holds max 2 electrons (6 total)Each dumbbell holds max 2 electrons (6 total)22ndnd energy level energy level

dd orbital orbital5 possible orbitals5 possible orbitals2 max electrons in each orbital (10 total)2 max electrons in each orbital (10 total)33rdrd energy level energy level

ff orbital orbital7 possible orbitals7 possible orbitalsComplex shapeComplex shape2 max electrons in each orbital (14 total)2 max electrons in each orbital (14 total)44thth energy level (highest) energy level (highest)

Valence electronsValence electronsOutermost electronsOutermost electrons Important in bonding with other atomsImportant in bonding with other atoms# can be found on your periodic table# can be found on your periodic table

6 24

carbon12.011

35 28

187

bromine79.904