IIIIII The Periodic Table History

P ZnAs Sb PtBi Midd CrMn Li K NOF Na BBe H AlSiCl CaTiVCoNiSeBr SrYZrNbMoRhPdCdTeI BaTaWOsIr Mg CeTbEr ThU Discovering the Periodic Table C S FeCu AgSn AuHgPb Ancient Times He ScGaGe RbRuIn CsTl PrNdSmGdDyHoTmYb La Ne Ar Kr Xe PoRn Ra EuLu Pa Ac Tc HfReAt Fr Pm NpPuAmCmBkCfEsFmMdNoLr Rf Db SgBhHsMt yJournal of Chemical Education, Sept. 1989

Dobereiner zJ.W. Dobereiner (1829, German) yPublished a classification system based on elemental triads xTriads – a set of three elements with similar properties

Dobereiner’s Periodic Table

Mendeleev zDmitri Mendeleev (1869, Russian) yOrganized elements by increasing atomic mass and periodicity. xPeriodicity – tendency of elements to repeat properties yElements with similar properties were grouped together. yThere were some discrepancies.

Mendeleev’s Periodic Table

Mendeleev yPredicted properties of undiscovered elements.

Moseley zHenry Mosely (1913, British) yOrganized elements by increasing atomic number. yResolved discrepancies in Mendeleev’s arrangement.

IIIIII Organization of the Elements The Periodic Table

Periodic Table Arrangment zPeriods (Rows) yHorizontal rows of elements yAll elements on a period have the same number of energy levels. zFamilies (Groups) yColumns yAll elements in a family have similar chemical properties and the same number of valence electrons.

Types of Elements Majority of elements; Left side of Table Metals Lustrous, ductile, malleable, mostly solids Conductors of heat and electricity Lose electrons to form positive ions (cations) 16 elements; Right side of Table Nonmetals Insulators Gases or brittle solids Either gain electrons to form negative ions (anions) or share electrons Stair Step between metals and nonmetals Metalloids B, Si, Ge, As, Sb, Te, Po Semiconductors of heat and electricity Either lose electrons to form positive ions (cations) or share electrons

zMetals zNonmetals zMetalloids Metallic Character

Periodic Table and Orbitals zMain block (representative) elements yGroups 1, 2, ys and p orbitals zTransition elements yGroups 3-12 yd orbitals zLanthanide Series yElements yf orbitals zActinide Series yElements yf orbitals

zMain Group Elements zTransition Metals zInner Transition Metals Blocks

s-block p-block d-block f-block

Families of the Periodic Table zGroup 1 yAlkali metals x1 val. e - xVery reactive metals xForm +1 ions. zGroup 2 yAlkaline earth metals x2 val. e - xForm +2 ions.

Families of the Periodic Table zGroups 3 – 12 yTransition metals xHave variable val. e - xCan form multiple cations. zGroup 13 yBoron group x3 val. e - xForm +3 ions.

Families of the Periodic Table zGroup 14 yCarbon group x4 val. e - xC can form +4 or –4 ions. xAll others form +2 or +4 ions. zGroup 15 yNitrogen group x5 val. e - xForm –3 ions (except for bismuth: +3)

Families of the Periodic Table zGroup 16 yChalcogens x6 val. e - xForm –2 ions. zGroup 17 yHalogens x7 val. e - xVery reactive nonmetals xForm –1 ions.

Families of the Periodic Table zGroup 18 yNoble gases x8 val. e - (exc. He) xDo not form ions.

alkaline earth metals halogens noble gases lanthanides alkali metals actinides coinage metals transition elements main block elements metalloids hydrogen more nonmetals more metals

Diatomic Moleculesements H2H2 N2N2 O2O2 F2F2 Cl 2 Br 2 I2I2 Tl At S Li Na K Fr Be Mg Ca Ra Sc Ac He Ne Ar Kr Rn Ti V Cr Mn Fe Co Ni Cu ZnGa Ge As Se Rb Sr Y Xe Zr Nb Mo Tc Ru Rh Pd Ag CdIn Sn Sb Te Cs Ba La Hf Ta W Re Os Ir Pt Au Hg Pb Bi Po Al Si P B C Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er TmYb Lu Th Pa U Np Pu Am Cm Bk Cf Es Fm MdNo Lr S Tl