- Slides: 20
Ch. 8 - The Periodic Table I. Periodic Trends I II III
Directions: z. Copy the information on the slides into your notes. z. Copy the arrows that you see on the slides onto your big periodic table. Label these arrows with the trend that is discussed on each of the slides.
A. Periodic Law z. When elements are arranged by increasing atomic #, elements with similar properties Show Video appear at regular intervals. Label arrows: Reactivity Decreases Increases
B. Atomic Radius z. Atomic Radius – size of a neutral atom (Decreases UP and to the RIGHT) Atomic Radius Decreases
B. Atomic Radius z. Why larger going down? y. Higher energy levels have larger orbitals with more electrons z. Why smaller to the right? y. Shielding - core e- block the attraction between the nucleus and the valence ey. Increased nuclear charge without additional shielding pulls e- in tighter
C. Ionization Energy z. First Ionization Energy- energy needed to remove the first electron. (Increases UP and to the RIGHT) Ionization Energy Increases
C. Ionization Energy z. Why opposite of atomic radius? y. In small atoms, e- are close to the nucleus where the attraction is stronger z. Why small jumps within each group? y. Stable e- configurations don’t want to lose electrons
C. Ionization Energy z. Successive Ionization Energies y. Large jump in ionization energy occurs when a CORE electron is removed. y. Mg Core e- 1 st I. E. 736 k. J 2 nd I. E. 1, 445 k. J 3 rd I. E. 7, 730 k. J
C. Ionization Energy z. Successive Ionization Energies y. Large jump in I. E. occurs when a CORE e- is removed. y. Al Core e- 1 st I. E. 577 k. J 2 nd I. E. 1, 815 k. J 3 rd I. E. 2, 740 k. J 4 th I. E. 11, 600 k. J
D. Electron Affinity y. Energy change when an atom gains an electron. Electron Affinity becomes more negative
D. Electron Affinity Fluorine: -328 KJ/mole F + e. Fy. Negative # means energy is released. This means fluorine wants to gain an electron. Neon: 29 KJ/mole Ne + e. Ney. Positive # means it takes energy. This means the element does not want to gain an electron.
E. Electronegativity z. Number assigned to an atom to represent the ability to attract electrons in a chemical bond (no units) (Increases UP and to the RIGHT) Electronegativity Increases
E. Electronegativity z. Why smaller going down? y. Elements such as Cesium and Francium rarely form bonds; Fr has 87 e(Example: Fr – 0. 7 – lowest number) z. Why larger to the right? y. These elements need fewer e- to form ions and therefore, chemical bonds (Example: F – 3. 98 – highest number)
F. Melting/Boiling Point (Exact melting and boiling points are on the big periodic table. ) Melting/Boiling Point - Highest in the middle of a period
G. Ionic Radius y. Cations (+) xlose ex. Get smaller y. Anions (–) xgain ex. Get larger © 2002 Prentice-Hall, Inc.
Examples: Circle the correct answer z. Which atom has the larger radius? y. Be or Ba y. Ca or Br
Examples z. Which atom has the higher 1 st I. E. ? y. N or Bi y. Baor Ne
Examples z. Which atom has the greatest electronegativity? y. Li or F y. As or Cu
Examples z. Which atom has the higher melting/boiling point? y. Li or C y. Cr or Kr
Examples z. Which particle has the larger radius? y. S or S 2 y. Al or Al 3+