Presentation on theme: "Unit 4: The Periodic Table"— Presentation transcript:
1 Unit 4: The Periodic Table ChemistryUnit 4: The Periodic Tableand PeriodicityOutlinePowerPoint Presentation by Mr. John Bergmann
2 The ElementsElement names come from a variety of sources.elements known to the ancients…S,Sn,C,Cuplace names…Fr,Po,Ge,Ga,Eu,Am,Cf,Scfamous people…Es,Fm,Md,No,Lr,Rf,Bhforeign languages…W,Fe,Au,Ag,Pb,Sn,Cumythology-related names…Th,Pm,Ta,Ti,Pdnames related to element properties…Hg,Xe
3 Background on the Periodic Table Dmitri Mendeleev: given creditfor Periodic Table (~1870)Mendeleev--organized Table byincreasing atomic mass--left spaces and predictedproperties of undiscoveredelementsMoseleyHenry Moseley: put elements inorder of increasing____________.atomic number
4 Describing the Periodic Table periodic law: the properties of elements repeatevery so oftenperiod:horizontal row; there are 7group (family):vertical column; there are 181817161514131291011876541321234675
5 Regions of the Tablemetals: left side of Table; form cationsproperties:malleable(can hammerinto shape)lustrous(shiny)ductile(can pullinto wire)good conductors(heat and electricity)
6 Regions of the Table (cont.) nonmetals: right side of Table; form anionsproperties:good insulatorsgases or brittle solidsneonsulfuriodinebromineNeS8I2Br2
7 Regions of the Table (cont.) metalloids (semimetals): “stair” between metalsand nonmetals(B, Si, Ge, As, Sb, Te, Po)metalsnonmetalscomputer chipsproperties:in-between those of metalsand nonmetals; “semiconductors”Si and Gecomputer chips
10 Same number of valence e– = similar properties Li Na1s2 2s11s2 2s2 2p6 3s1In any group, the element BELOW has one moreoccupied energy level than does the element ABOVE.Li NaThe period that an element is in is the same as theenergy level that its valence electrons are in.Li Nain 2nd periodin 3rd periodv.e– in 2nd E.L.v.e– in 3rd E.L.
11 Periodicitythere are trends in properties of elements-- left-right AND up-down trendsatomic radius:the size of a neutral atom…increases as we goWHY?add a new energylevel each time…decreases as we goWHY?it has to do with…coulombic attraction: attraction between (+) and (–)
12 Coulombic attraction depends on… 2–2+1–1+amount of chargedistance between chargesAs we go , more coulombic attraction, no new energy level, more pull, smaller size+–+–+–HHe+–
13 shielding effect: kernel e– “shield” valence e– from attractive force of the nucleusKv.e–Liv.e–tougher to removeeasierto remove-- caused by kernel and valence e–repelling each otherAs we go , shielding effect increases.
14 ionic radius:the size of an ioncationsanionsCa atomCa2+ ionCl atomCl1– ion20 p+20 p+17 p+17 p+20 e–18 e–17 e–18 e–Cl1–CaClCa2+cations are smalleranions are larger
15 ionization energy: the energy required to remove an e– from an atom M + 1st I.E.M e–removes 1st e–M + 2nd I.E.M e–M + 3rd I.E.M e–Each successive ionization requiresmore energy than the previous one.As we go , 1st I.E….decreases.(due to the shielding effect)As we go , 1st I.E….increases.
16 electronegativity:the tendency fora bonded atom toattract e– to itselfLinus Pauling quantifiedthe electronegativity scale.As we go , electronegativity…decreases.As we go , electronegativity…increases.electronegativity increases
18 Resources - Periodic Table ObjectivesEpisode 7 – The Periodic TableWorksheet - vocabularyActivity - aliens cards: A B keyActivity - coloring periodic tableWorksheet - periodic table paragraphWorksheet - ionization energiesVideo 07: Periodic Table The development and arrangement of the periodic table of elements is examined. (added 2006/10/08) World of Chemistry > 08: Chemical BondsLab - periodic trends databaseProject - element brochure example timelineWorksheet - periodic table textbook questionsOutline (general)