Unit 4: The Periodic Table and Periodicity

1. Chemistry Unit 4: The Periodic Table and Periodicity Outline PowerPoint Presentation by Mr. John Bergmann

2. The Elements Element names come from a variety of sources. Sn, C, Cu elements known to the ancients… S, place names… Ga, Cf, Fr, Po, Ge, Eu, Sc Am, Es, Lr, Rf, Bh Fm, Md, No, famous people… Fe, Au, Ag, Sn, foreign languages… W, Pb, Cu mythology-related names… Th, Pm, Ta, Ti, Pd names related to element properties… Hg, Xe

3. Mendeleev Moseley Background on the Periodic Table Dmitri Mendeleev: given credit for Periodic Table (~1870) -- organized Table by increasing atomic mass -- left spaces and predicted properties of undiscovered elements Henry Moseley: put elements in order of increasing ____________. atomic number

4. 18 1 16 17 14 15 13 1 2 2 12 3 4 5 6 8 10 11 7 9 3 4 5 6 7 Describing the Periodic Table periodic law: the properties of elements repeat every so often period: horizontal row; there are 7 group (family): vertical column; there are 18

5. lustrous (shiny) malleable (can hammer into shape) ductile (can pull into wire) good conductors (heat and electricity) Regions of the Table metals: left side of Table; form cations properties:

6. Regions of the Table (cont.) nonmetals: right side of Table; form anions good insulators gases or brittle solids properties: neon sulfur iodine bromine Ne S8 I2 Br2

7. nonmetals metals computer chips Si and Ge Regions of the Table (cont.) metalloids (semimetals): “stair” between metals and nonmetals (B, Si, Ge, As, Sb, Te, Po) properties: in-between those of metals and nonmetals; “semiconductors” computer chips

8. group 1 (except H); 1+ charge; very reactive alkali metals: group 2; 2+ charge; less reactive than alkalis alkaline earth metals: group 17; 1– charge; very reactive halogens: noble gases: group 18; no charge; unreactive lanthanides: elements 58–71 contain f orbitals actinides: elements 90–103 group 11 coinage metals: groups 3–12; variable charges transition elements: groups 1, 2, 13–18 main block (representative) elements:

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

10. Li Na Same number of valence e– = similar properties Li Na 1s22s1 1s2 2s2 2p63s1 In any group, the element BELOW has one more occupied energy level than does the element ABOVE. Li Na The period that an element is in is the same as the energy level that its valence electrons are in. in 2nd period in 3rd period v.e– in 3rd E.L. v.e– in 2nd E.L.

11. …increases as we go …decreases as we go Periodicity there are trends in properties of elements -- left-right AND up-down trends atomic radius: the size of a neutral atom WHY? add a new energy level each time WHY? it has to do with… coulombic attraction: attraction between (+) and (–)

12. amount of charge distance between charges 2– 2– 2+ 2+ 2+ 2– 1– 1+ As we go , more coulombic attraction, no new energy level, more pull, smaller size – + + + – – Coulombic attraction depends on… + – – + H He

13. v.e– v.e– Li K As we go , shielding effect increases. shielding effect: kernel e– “shield” valence e– from attractive force of the nucleus tougher to remove easier to remove -- caused by kernel and valence e– repelling each other

14. Ca Cl Cl1– Ca2+ ionic radius: the size of an ion cations anions Ca atom Ca2+ ion Cl1– ion Cl atom 17 p+ 20 p+ 17 p+ 20 p+ 17 e– 18 e– 20 e– 18 e– cations are smaller anions are larger

15. removes 1st e– M + 2nd I.E. M + 3rd I.E. As we go , 1st I.E…. As we go , 1st I.E…. ionization energy: the energy required to remove an e– from an atom M + 1st I.E. M1+ + e– M2+ + e– M3+ + e– Each successive ionization requires more energy than the previous one. decreases. (due to the shielding effect) increases.

16. As we go , electronegativity… As we go , electronegativity… electronegativity increases electronegativity: the tendency for a bonded atom to attract e– to itself Linus Pauling quantified the electronegativity scale. decreases. increases.

17. Resources - Periodic Table Objectives Episode 7 – The Periodic Table Worksheet - vocabulary Activity - aliens cards: ABkey Activity - coloring periodic table Worksheet - periodic table paragraph Worksheet - ionization energies Lab - periodic trends database Project - element brochure example timeline Worksheet - periodic table textbook questions Outline (general)