Atoms and the Periodic TableChapter 12Chapter 12Pages 285-305click here for 9/page to printAtoms are smallAtoms are smallSmaller than light wavesSmaller than light wavesPeriodic tablePeriodic tableActual arrangement doesn’t fit on page very wellPeriodic TablePeriodic TableAtomic symbolAtomic symbolOnly first letter is capitalOnly first letter is capitalCO is not cobalt (Co)CO is not cobalt (Co)Cloud Model of AtomCloud Model of AtomAtomic StructureAtomic Structure• Protons•NeutronsNeutrons• ElectronsAtomic StructureProtonsAtomic Structure--Protons Electrical charge +1 Equal number of negative electronsBalance to zero chargeBalance to zero charge Atomic number is # of protons Mass = 1 atomic mass unit (u)Atomic StructureNeutronsAtomic Structure--NeutronsEl t i l h 0Electrical charge = 0 Mass = 1 atomic unit Number of neutrons is not set foranatomofanelementfor an atom of an elementAtomic StructureNucleusAtomic Structure--Nucleus• Protons--set number, determines the element• Neutrons—no set number, can be different for same elementdifferent for same elementMake up the NUCLEUSNEW KLEE USNlhNucleons—have massNEW KLEE ONSAtomic StructureElectronsAtomic Structure--Electrons Electrical charge -1 Mass = almost nothing(1/1837 of a proton)(1/1837 of a proton)Atomic model analogyAtomic model analogyhttp://www.sportslighting.com/feature/ls.htmlAnalogy ofAnalogy of atom--conthttp://www.joesentell.com/panther/panther.htmhttp://web.ics.purdue.edu/~drhodes/hort410/vgsd13.htmhttp://www.skynet.ie/~ceason/cormac/stuff/housefly_anim.gifPeriodic Table codinggaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa• Metals, metalloids and nonmetalsaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaPeriods and GroupsPeriods and GroupsAtomic size across periodsAtomic size across periodsGroups (families)Groups (families)N1316 b l t t h d•Name groups 13-16 by element at headElectron wavesElectron waves• Certain energy and location function of wavelength—right diagram is not sustainableShell Model of AtomsShell Model of AtomsElectrons shells in periodic tableElectrons shells in periodic table• First three periodsAtomic StructureElectronsAtomic Structure--ElectronsModeled in energy shells•First shell2 electronsFirst shell2 electrons• Second shell 8 electrons• Third shell 8 electronsAnalogy of atomcontAnalogy of atom--conthttp://www.joesentell.com/panther/panther.htmhttp://web.ics.purdue.edu/~drhodes/hort410/vgsd13.htmhttp://www.skynet.ie/~ceason/cormac/stuff/housefly_anim.gifPeriodic Tableeodc abe• Metals, nonmetals and metalloidsand metalloidsInner transition metalsInner transition metalsAtomic StructureAtomic StructureAtomic Number = number of protonsp Controls properties of elements Constant number for all atoms of the same elementAtoms of the same substance may have different bftnumbers of neutrons• ISOTOPES of the same element described by mass numbermass number• Atomic mass of element is average mass of isotopes that occur in natureisotopes that occur in natureElectrons have negligible mass and are present in a cloud surrounding the nucleus—modeled with gshells, but actually random
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