1. Chapter 6: The Periodic Table
6.1 Organizing the Elements

2. I. Early Organizing Principles
A. Element properties used to sort them into groups
B. First organized into triads, didn’t work with all
Chlorine
Iodine
Bromine
C. Mendeleev: organized based on increasing atomic mass, left empty spaces for unknown elements based on keeping common properties
D. Later missing elements found

3. II. Modern Periodic Table
A. Some elements violated Mendeleev’s order (Tellurium and Iodine)
B. Modern table uses atomic number
C. Rows are called “Periods”
D. Periodic Law: if elements organized by increasing atomic number, there is periodic repetition of physical and chemical properties

4. III. Major Categories
A. Metals: good conductors of heat and electricity, shiny, solid at room temp. (except Hg), ductile, malleable
B. Non-metals: poor conductors (except Carbon), brittle solids, liquids, or gases
C. Metalloids: similar properties to both metals and non-metals based on conditions

5. 6.2 Classifying the Elements
Sodium Silicon Argon

6. I. Groups (Columns)
A. Alkali metals: very reactive metals with oxygen or water
B. Alkali Earth metals: all have two outer electrons and tend to form +2 charged ions
C. Transition metals: when compounds with them
are dissolved in water, they form colored solutions

7. D. Inner Transition metals: many of these elements are man-made
E. Halogens: very reactive non-metals
F. Noble gases: very stable elements

8. II. E- Configurations in Groups
A. Noble gases: have complete outer orbitals (ex. Ne)
B. Representative elements: have incomplete S or P orbitals (ex. S)
C. Transition metals: end on D-orbitals (ex. Fe)
D. Inner transition metals: end on F-orbitals (ex. Ce)

9. 6.3 PERIODIC TRENDS

10. I. Atomic Size A. One factor is # of electron orbitals
B. Also based on charge of nucleus
C. Increases down P.T., and from right to left
Increasing atomic size
Increasing atomic size

11. II. Ionic Size
A. Cations (+ ions) smaller than their atoms since less electrons
B. Anions (- ions) larger than atoms, more electrons
C. Trend related to atomic size but not exactly same

12. III. Ionization Energy A. Energy required to remove electrons
Increasing Ionization energy
A. Energy required to remove electrons
B. Every additional e- removed requires more energy
C. Increases up P.T, from left to right
Increasing ionization energy

13. IV. Why Remove Electrons?
A. Atoms gain or lose e- to become more stable
B. Full S and P orbitals (8 e-) more stable than partially filled ones
C. Ex.
Sodium will lose 1 e- and carry a 1+ charge, Fluorine will gain 1 e- and carry a 1- charge

14. V. Electronegativity
A. Ability of atoms to attract electrons to itself
B. Based on stability of elements
C. Increases up P.T., and left to right
Increasing electronegativity
Increasing electronegativity