Lesson C4.1 http://www.rsc.org/Education/Teachers/Resources/ptdata/welcome.htm www.webelements.com http://www.rsc.org/periodic-table/ www.periodicvideos.com Lesson C4.4 www.wfu.edu/~ylwong/balanceeq/balanceq.html http://members.misty.com/don/spectra.html Lesson C4.12 ...