Chapter 4 - Chapter 4 - Atomic StructureAtomic Structure

Notes on 4.1 - 4.3Notes on 4.1 - 4.3

AtomsAtoms

History of the History of the AtomAtom

The discovery of the The discovery of the electron…electron…

J.J. Thomson’s ModelJ.J. Thomson’s Model

Rutherford and the nucleusRutherford and the nucleus

400 BC 1803 1904 1910 1913 1926

Niels Bohr

J J Thomson

Democratus

John Dalton

Schroedinger / Heisenberg

Ernest Rutherford

Atomic Theory

Parts of an AtomParts of an Atom

Parts of an Atom:

ParticleParticle chargecharge massmass locationlocation

ProtonProton

NeutronNeutron

ElectronElectron

QuarksQuarks

Atomic NumberAtomic Number

Mass NumberMass Number

Atomic Mass UnitsAtomic Mass Units

Mass of an AtomMass of an Atom

IsotopesIsotopes

Isotopes of HydrogenIsotopes of HydrogenHydrogen has three isotopes:

•Hydrogen-1

•Hydrogen-2

•Hydrogen-3

Hydrogen-1Hydrogen-1 Hydrogen-2Hydrogen-2 Hydrogen-3Hydrogen-3

mass = 1mass = 1

1 proton1 proton 1 proton1 proton 1 proton1 proton

0 neutrons0 neutrons

Atomic # =1Atomic # =1 Atomic # =Atomic # = Atomic # =Atomic # =

Bohr Model vs. Rutherford Bohr Model vs. Rutherford ModelModel

What is an energy level?What is an energy level?

Energy Levels and the AtomEnergy Levels and the Atom

Energy Level Diagram

Important Energy Level RulesImportant Energy Level Rules

Potassium - 19 total electrons

1 level - 2 3rd level - 8

2nd level - 8 4th level - 1

The Electron Cloud ModelThe Electron Cloud Model

Atomic OrbitalsAtomic Orbitals

Can we see atoms?Can we see atoms?

STM Images of an AtomSTM Images of an Atom