Periodicity Assistance
I found this online quiz to practice periodicity: http://www.roomd113.com/AP%20PRACTICE%20TEST/periodct.htm
Also, http://library.thinkquest.org/28330/Learn/Chapter_12/chapter_12.html looks like a good, informative site.
Please recall that your Adopt an Element projects are due on Monday, at the beginning of the period. We have a lab on Monday and will test on periodicity on Wednesday.