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History

History. Ch. 5 - The Periodic Table. Mendeleev. Dmitri Mendeleev (1869, Russian) Organized by increasing atomic mass . Grouped by properties Some discrepancies . Mendeleev (continued). Dmitri Mendeleev (1869, Russian) Predicted properties of undiscovered elements. Moseley.

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History

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  1. History Ch. 5 - The Periodic Table

  2. Mendeleev • Dmitri Mendeleev (1869, Russian) • Organized by increasing atomic mass. • Grouped by properties • Some discrepancies.

  3. Mendeleev (continued) • Dmitri Mendeleev (1869, Russian) • Predicted properties of undiscovered elements.

  4. Moseley • Henry Moseley (1913, British) • Organized by increasing atomic number. • Resolved discrepancies in Mendeleev’s arrangement.

  5. Organization of theElements

  6. Metallic Character • Metals • Nonmetals • Metalloids

  7. Blocks Main group • s • p • d • f

  8. Chemical Reactivity • Families • Similar valence e- within a group result in similar chemical properties • They have similar valence configurations

  9. Chemical Reactivity • s1 • s2 • d-block • f-block • s2p5 • s2p6 • Alkali Metals • Alkaline Earth Metals • Transition metals • Inner transition metals • Halogens • Noble Gases

  10. Metallic Character

  11. Metallic Character

  12. Metallic Character

  13. Metallic Character

  14. Practice Choose from the following list of elements to answer the questions below: Gold (Au) Oxygen (O) Krypton (Kr) Silicon (Si) Magnesium (Mg) Iron (Fe) Boron (B) Sulfur (S) Which elements you would expect to be: Brittle: Sulfur, (Oxygen and Krypton would be if they were solid, but they’re both gases at room temperature) Malleable: Gold, Magnesium, Iron Conductive: Gold, Magnesium, Iron Somewhat brittle but somewhat malleable: Boron, Silicon Shiny: Gold, Magnesium, Iron Poor conductors: Sulfur, Oxygen, Krypton

  15. Practice Write the noble-gas notation for the electron configuration of calcium. In which period does it belong? Ca Noble gas notation: [Ar]4s2 Period: 4 [Ne]3s23p5 Element name: Chlorine Period: 3 Group number: 17 Metallic character: Nonmetal Block: p-block Group (family) name: halogens

  16. Determining number of Valence electrons • Same number as group number (subtract 10 for elements after d-block), or just count over from the beginning of the period on the periodic table (but skip d-block) How many valence electrons does each element have? N O S Al Cl K Mg 3 5 6 6 7 1 2

  17. Formation of Ions • An atom gains or loses electrons to reach a full shell • The number of electrons gained or lost determines the charge of the ion Lose electrons – Positive ion – CATION Gain electrons – Negative ion - ANION

  18. Periodic Trends Ch. 5 - The Periodic Table

  19. Periodic Law (Periodicity) • When elements are arranged in order of increasing atomic number, elements with similar properties appear at regular intervals.

  20. Chemical Reactivity • Alkali Metals • Alkaline Earth Metals • Transition metals • Halogens • Noble Gases

  21. Properties: • Atomic Radius Size of an atom • Electronegativity Ability of a bonded atom to attract electrons • Electron Affinity How much a neutral atom wants to gain an electron

  22. Atomic Radius • Atomic Radius K Na Li Ar Ne

  23. Atomic Radius • Atomic Radius – size of atom Increases to the LEFT and DOWN

  24. Atomic Radius • Why larger going down? • Higher energy levels have larger shells • Shielding - core e- block the attraction between the nucleus and the valence e- • Why smaller to the right? • Increased nuclear charge without additional shielding pulls e- in tighter

  25. Which atom has the larger radius? Why? • Be or Ba Ba: it has higher energy levels (larger shells), plus shielding • Ca or Br Ca: both are in the same energy level, but there is less nuclear charge for Ca, so electrons are not held as tightly

  26. Electron affinity • Electron affinity Increases UP and to the RIGHT, Does NOT include noble gases

  27. Which atom has the greater electron affinity? Why? • Na or F? F: It’s a smaller atom and holds electrons more strongly; nearly a full shell • O or Se O: smaller atom, attracts electrons more strongly

  28. Electronegativity • Atoms must be BONDED for electronegativity to be measured • Fluorine the most electronegative atom

  29. Electronegativity • Electronegativity Increases UP and to the RIGHT, Does NOT include noble gases

  30. Which atom has the greater electronegativity? Why? • Rb or F? F: Fluorine is THE most electronegative atom; small atom and nearly a full shell • S or P? S: smaller atom attracts electrons more strongly, shell closer to being full

  31. Ionic Radius • Cations Lose electrons - smaller • Anions Gain electrons – bigger

  32. Examples • Which particle has the larger radius? • S or S2- • Al or Al3+ S2- Al

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