1. CHEMISTRY 1000 Topics of Interest #1: Updating the Periodic Table

2. Changing the Periodic Table? “For the first time in history, a change will be made to the atomic weights of some elements listed on the Periodic table of the chemical elements posted on walls of chemistry classrooms and on the inside covers of chemistry textbooks worldwide.” 1 “… As technology improved, we have discovered that the numbers on our chart are not as static as we have previously believed," says Dr. Michael Wieser, an associate professor at the University of Calgary, who serves as secretary of the International Union of Pure and Applied Chemistry's (IUPAC) Commission on Isotopic Abundances and Atomic Weights. 1 1 ScienceDaily. Retrieved September 14, 2011, from http://www.sciencedaily.com/releases/2010/12/http://www.sciencedaily.com/releases/2010/12/ 101215133325.htm101215133325.htm (original source: Pure Appl. Chem., 2011, Vol. 83, No. 2, pp. 359-396)

3. Changing the Periodic Table? The elements affected? Hydrogen Lithium Boron Carbon Nitrogen Oxygen Silicon Sulfur Chlorine Thallium Except for thallium (Tl), these are among the most abundant elements on Earth! 1 ScienceDaily. Retrieved September 14, 2011, from http://www.sciencedaily.com/releases/2010/12/http://www.sciencedaily.com/releases/2010/12/ 101215133325.htm101215133325.htm (original source: Pure Appl. Chem., 2011, Vol. 83, No. 2, pp. 359-396)

4. Changing the Periodic Table? How large are the ranges? Hydrogen: 1.00784 u to 1.00811 u Lithium: 6.938 u to 6.997 u Boron: 10.806 u to 10.821 u Carbon: 12.0096 u to 12.0116 u Nitrogen: 14.00643 u to 14.00728 u Oxygen: 15.99903 u to 15.99977 u Silicon: 28.084 u to 28.086 u Sulfur: 32.059 u to 32.076 u Chlorine: 35.446 u to 35.457 u Thallium: 204.382 u to 204.385 u All these elements have multiple isotopes. Why must this be? 1 ScienceDaily. Retrieved September 14, 2011, from http://www.sciencedaily.com/releases/2010/12/http://www.sciencedaily.com/releases/2010/12/ 101215133325.htm101215133325.htm (original source: Pure Appl. Chem., 2011, Vol. 83, No. 2, pp. 359-396)