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Unit 4: The Periodic Table and Periodicity

Chemistry. Unit 4: The Periodic Table and Periodicity. The Origin of Elements. Element names come from a variety of sources . Cu, . Sn, . C, . Au . elements known to the ancients… . S,. place names… . Ga, . Cf,. Fr, . Po, . Ge, . Eu, . Sc . Am, . Ro?. famous people… . Bh, .

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Unit 4: The Periodic Table and Periodicity

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  1. Chemistry Unit 4: The Periodic Table and Periodicity

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

  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. ? ? ? Mendeleev’s Early Periodic Table TABELLE II GRUPPE I GRUPPE II GRUPPE III GRUPPE IV GRUPPE V GRUPPE VI GRUPPE VII GRUPPE VIII ___ ___ ___ ___ RH4 RH3 RH2 RH R2O RO R2O3 RO2 R2O5 RO3 R2O7 RO4 REIHEN 1 2 3 4 5 6 7 8 9 10 11 12 H = 1 Li = 7 Be = 9.4 B = 11 C = 12 N = 14 O = 16 F = 19 Na = 23 Mg = 24 Al = 27.3 Si = 28 P = 31 S = 32 Cl = 35.5 K = 39 Ca = 40 __ = 44 Ti = 48 V = 51 Cr = 52 Mn = 55 Fe = 56, Co = 59, Ni = 59, Cu = 63 (Cu = 63) Zn = 65 __ = 68 __ = 72 As = 75 Se = 78 Br = 80 Rb = 85 Sr = 87 ? Yt = 88 Zr = 90 Nb = 94 Mo = 96 __ = 100 Ru = 104, Rh = 104, Pd = 106, Ag = 108 (Ag = 108) Cd = 112 In = 113 Sn = 118 Sb = 122 Te = 125 J = 127 Cs = 133 Ba = 137 ? Di = 138 ? Ce = 140 __ __ __ __ __ __ __ ( __ ) __ __ __ __ __ __ __ __ ? Er = 178 ? La = 180 Ta = 182 W = 184 __ Os = 195, Ir = 197, Pt = 198, Au = 199 (Au = 199) Hg = 200 Tl= 204 Pb = 207 Bi = 208 __ __ __ __ __ Th = 231 __ U = 240 __ __ __ __ __ From Annalen der Chemie und Pharmacie, VIII, Supplementary Volume for 1872, p. 151.

  5. Elements Properties are Predicted O’Connor Davis, MacNab, McClellan, CHEMISTRY Experiments and Principles 1982, page 119,

  6. 1894-1918 Ancient Times Midd. -1700 1923-1961 H He 1735-1843 1965- 1965- 1965- 1843-1886 Li Be B C N O F Ne Na Mg Al Si P S Cl Ar K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe Cs Ba La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn Ds Rg Cn Uut Fl Uup Fr Ra Ac Lv Rf Db Uus Uuo Sg Bh Hs Mt Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr Discovering the Periodic Table Journal of Chemical Education, Sept. 1989

  7. 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

  8. Dutch Periodic Table 118 117 116 115 114 113 112 111 110 109 108 107 106 Strong, Journal of Chemical Education, Sept. 1989, page 743

  9. How to Organize Elements… Periodic Table Designs

  10. 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:

  11. 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

  12. 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

  13. 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:

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

  15. 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.

  16. …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 (–)

  17. 2– 2+ 2– 2+ 1– 1+ 2+ 2– As we go , more coulombic attraction, no new energy level, more pull, smaller size – + + + – – Coulombic attraction depends on… amount of charge distance between charges + – H He

  18. Atomic Radii of Representative Elements (nm) 1A 2A 3A 4A 5A 6A 7A Li Be C N O B F 0.088 0.077 0.070 0.066 0.064 0.152 0.111 Na Mg Al Si P S Cl 0.186 0.160 0.143 0.117 0.110 0.104 0.099 K Ca Ge As Se Br Ga 0.231 0.197 0.122 0.122 0.121 0.117 0.114 Rb Sr In Sn Sb Te I 0.162 0.140 0.141 0.137 0.133 0.244 0.215 Cs Ba At Pb Tl Po Bi 0.262 0.217 0.171 0.175 0.146 0.140 0.140 LeMay Jr, Beall, Robblee, Brower, Chemistry Connections to Our Changing World , 1996, page 175

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

  20. Ca Cl Cl– Ca2+ ionic radius: the size of an ion cations anions Ca atom Ca2+ ion Cl– 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

  21. IA IIA IIIA IVA VA VIA VIIA N3- Li1+ Be2+ Li O2- F1- = 1 Angstrom Be C N O B F 0.88 0.77 0.70 0.66 0.64 1.71 1.40 1.36 1.52 1.11 0.60 0.31 Na Na1+ Mg2+ S2- Cl1- Al3+ Mg Al Si P S Cl 0.95 0.65 1.86 1.60 0.50 1.84 1.81 1.43 1.17 1.10 1.04 0.99 K Ca Se2- Br1- Ge As Se Br Ga Ga3+ K1+ Ca2+ 2.31 1.97 1.33 0.99 1.22 1.22 1.21 1.17 1.14 0.62 1.98 1.85 Rb Sr Te2- I1- In In3+ Sn Sb Te I Rb1+ Sr2+ 1.62 1.40 1.41 1.37 1.33 0.81 2.21 2.16 2.44 2.15 1.48 1.13 Cs Ba Pb Tl Tl3+ Cs1+ Bi Ba2+ 2.62 2.17 1.69 1.35 0.95 1.71 1.75 1.46 = 1 Angstrom or 10-10 m Atomic Radii Ionic Radii IA IIA IIIA IVA VA VIA VIIA

  22. removes 1st e– M+ + 2nd I.E. M2+ + 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 = metal M + 1st I.E. M+ + e– M2+ + e– M3+ + e– Each successive ionization requires more energy than the previous one. decreases. (due to the shielding effect) increases.

  23. Shaded area on table denotes core electrons. Ionization Energies (kJ/mol) 3rd 6910 7730 2740 3220 2905 3375 3850 3945 4th 9540 10,600 11,600 4350 4950 4565 5160 5770 Element Na Mg Al Si P S Cl Ar 1st 498 736 577 787 1063 1000 1255 1519 2nd 4560 1445 1815 1575 1890 2260 2295 2665 5th 13,400 13,600 15,000 16,100 6270 6950 6560 7320 6th 16,600 18,000 18,310 19,800 21,200 8490 9360 8780 Herron, Frank, Sarquis, Sarquis, Cchrader, Kulka, Chemistry 1996, Heath, page

  24. 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 Fluorine is the most electro-negative element

  25. H 2.1 Li 1.0 Be 1.5 B 2.0 C 2.5 N 3.0 O 3.5 F 4.0 Na 0.9 Mg 1.2 Al 1.5 Si 1.8 P 2.1 S 2.5 Cl 3.0 K 0.8 Ca 1.0 Sc 1.3 Ti 1.5 V 1.6 Cr 1.6 Mn 1.5 Fe 1.8 Co 1.8 Ni 1.8 Cu 1.9 Zn 1.7 Ga 1.6 Ge 1.8 As 2.0 Se 2.4 Br 2.8 Rb 0.8 Sr 1.0 Y 1.2 Zr 1.4 Nb 1.6 Mo 1.8 Tc 1.9 Ru 2.2 Rh 2.2 Pd 2.2 Ag 1.9 Cd 1.7 In 1.7 Sn 1.8 Sb 1.9 Te 2.1 I 2.5 * Cs 0.7 Ba 0.9 La 1.1 Hf 1.3 Ta 1.5 W 1.7 Re 1.9 Os 2.2 Ir 2.2 Pt 2.2 Au 2.4 Hg 1.9 Tl 1.8 Pb 1.8 Bi 1.9 Po 2.0 At 2.2 y Fr 0.7 Ra 0.9 Ac 1.1 * Lanthanides: 1.1 - 1.3 y Actinides: 1.3 - 1.5 Below 1.0 2.0 - 2.4 1.0 - 1.4 2.5 - 2.9 1.5 - 1.9 3.0 - 4.0 Electronegativities 1A 8A 1 1 3A 5A 7A 2A 4A 6A 2 2 3 3 2B 4B 6B 8B 1B 3B 5B 7B Period 4 4 5 5 6 6 7 Hill, Petrucci, General Chemistry An Integrated Approach 2nd Edition, page 373

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