1. Prentice-Hall © 2007 General Chemistry: Chapter 9 Slide 1 of 35 Dr. Juana Mendenhall Assistant Professor Morehouse College Lecture 1 CHEMISTRY Ninth Edition GENERAL Principles and Modern Applications Petrucci Harwood Herring Madura Chapter 9: The Periodic Table and Some Atomic Properties

2. Prentice-Hall © 2007 General Chemistry: Chapter 9 Slide 2 of 35 Objectives 1Define and locate periods, groups, families, and transition elements on the periodic table 2Define & explain metals and nonmetals and their ions 3Define atomic size and indicate factors that influence atomic size, such as covalent, ionic, metallic, and van der Waals radii 1Indicate the trends that affect atomic size using the periodic table 4Define and indicate ionization energy and relate trends using the periodic table 5Define electron affinity & relate trends to the periodic table

3. Prentice-Hall © 2007 General Chemistry: Chapter 9 Slide 3 of 35 Classifying the Elements: The Periodic Law and the Periodic Table  1869, Dimitri Mendeleev Lother Meyer When the elements are arranged in order of increasing atomic mass, certain sets of properties recur periodically.

4. Prentice-Hall © 2007 General Chemistry: Chapter 9 Slide 4 of 35 Mendeleev’s Periodic Table 1871 — = 44 — = 72 — = 68 — = 100

5. Prentice-Hall © 2007 General Chemistry: Chapter 9 Slide 5 of 35 Periodic Law States that the physical & chemical ppts of the elements vary with atomic number

6. Prentice-Hall © 2007 General Chemistry: Chapter 9 Slide 6 of 35 The Periodic table Alkali MetalsAlkaline EarthsTransition MetalsHalogensNoble Gases Lanthanides and Actinides Main Group

7. Prentice-Hall © 2007 General Chemistry: Chapter 9 Slide 7 of 35 Trends in electron configurations Group 1A Li [He]2s 1 Na [Ne]3s 1 K [Ar]4s 1 Rb [Kr]5s 1 Cs[Xe]6s 1 Fr[Rn]7s 1 Group 2A Be [He]2s 2 Mg [Ne]3s 2 Ca[Ar]4s 2 Sr [Kr]5s 2 Ba[Xe]6s 2 Ra[Rn]7s 2 Valence electrons: outer electrons of an atom that are involved in chemical bonding

8. Prentice-Hall © 2007 General Chemistry: Chapter 9 Slide 8 of 35 Metals and Nonmetals and Their Ions  Metals  Good conductors of heat and electricity.  Malleable and ductile.  Moderate to high melting points.  Nonmetals  Nonconductors of heat and electricity.  Brittle solids.  Some are gases at room temperature.

9. Prentice-Hall © 2007 General Chemistry: Chapter 9 Slide 9 of 35 Metallic Character Increase Increase in non-metallic character

10. Prentice-Hall © 2007 General Chemistry: Chapter 9 Slide 10 of 35 Metals Tend to Lose Electrons

11. Prentice-Hall © 2007 General Chemistry: Chapter 9 Slide 11 of 35 Nonmetals Tend to Gain Electrons

12. Prentice-Hall © 2007 General Chemistry: Chapter 9 Slide 12 of 35 Electron Configurations of Cations and Anionsof Some Ions Cations Na [Ne]3s 1 Na + [Ne] Ca[Ar]4s 2 Ca 2+ [Ar] Al[Ne]3s 2 3p 1 Al 3+ [Ne] Anions H 1s 1 H - 1s2 F 1s 2 2s 2 2p 5 F - 1s 2 2s 2 2p 6

13. Prentice-Hall © 2007 General Chemistry: Chapter 9 Slide 13 of 35 Sizes of Atoms and Ions Physical properties such as density, melting point, and boiling point are related to size of atoms. Atomic radius: is one-half the distance b/w the two nuclei in two adjacent metal atoms; elements that exist as diatomic molecules the atomic radius is one-half the distance b/w the nuclei of the two atoms in a particular molecule

14. Prentice-Hall © 2007 General Chemistry: Chapter 9 Slide 14 of 35 Atomic Radius Increase

15. Prentice-Hall © 2007 General Chemistry: Chapter 9 Slide 15 of 35 Screening and Penetration Z eff = Z – S Z is nuclear charge & S is the shielding constant E n = - RHRH n2n2 Z eff 2

16. Prentice-Hall © 2007 General Chemistry: Chapter 9 Slide 16 of 35 Ionization Energy Mg(g) → Mg + (g) + e - I 1 = 738 kJ Second Ionization energy, I 2, is the energy needed to remove the second electron Mg + (g) → Mg 2+ (g) + e - I 2 = 1451 kJ I = R H n2n2 Z eff 2 Ionization energy: measures how strongly an atom hold its electrons. Ioniziation energy is the minimum energy required to remove an electron from the ground state of the isolated gaseous atom. First Ionization energy, I 1, is the energy needed to remove the first e -

17. Prentice-Hall © 2007 General Chemistry: Chapter 9 Slide 17 of 35 First Ionization Energy, I 1 Increase

18. Prentice-Hall © 2007 General Chemistry: Chapter 9 Slide 18 of 35 Electron Affinity F(g) + e - → F - (g) EA = -328 kJ F(1s 2 2s 2 2p 5 ) + e - → F - (1s 2 2s 2 2p 6 ) Li(g) + e - → Li - (g) EA = -59.6 kJ Measures the energy change (attraction or affinity) that occurs when an electron is accepted by atom in the gaseous state. We assign a (-) value to the electron affinity when energy is released. The more (-) the EA, the greater the tendency the atom can accept an e -

19. Prentice-Hall © 2007 General Chemistry: Chapter 9 Slide 19 of 35 First Electron Affinities

20. Prentice-Hall © 2007 General Chemistry: Chapter 9 Slide 20 of 35 Second Electron Affinities O(g) + e - → O - (g) EA = -141 kJ O - (g) + e - → O 2- (g) EA = +744 kJ

21. Prentice-Hall © 2007 General Chemistry: Chapter 9 Slide 21 of 35 Magnetic Properties  Diamagnetic atoms or ions:  All e - are paired.  Weakly repelled by a magnetic field.  Paramagnetic atoms or ions:  Unpaired e -.  Attracted to an external magnetic field.

22. Prentice-Hall © 2007 General Chemistry: Chapter 9 Slide 22 of 35 Paramagnetism

23. Prentice-Hall © 2007 General Chemistry: Chapter 9 Slide 23 of 35 Periodic Properties of the Elements