http://en.wikipedia.org/wiki/Radioactive_decay [2]
http://hyperphysics.phy-astr.gsu.edu/hbase/nuclear/radact.html [3]
http://www2.lbl.gov/abc/wallchart/chapters/03/0.html [4]
http://chemistry.about.com/od/chemistryfaqs/f/radioactivity.htm [5]
http://www.britannica.com/EBchecked/topic/489089/radioactivity [6]
Links
[1] https://hootsgo.org/?q=node/6400
[2] http://en.wikipedia.org/wiki/Radioactive_decay
[3] http://hyperphysics.phy-astr.gsu.edu/hbase/nuclear/radact.html
[4] http://www2.lbl.gov/abc/wallchart/chapters/03/0.html
[5] http://chemistry.about.com/od/chemistryfaqs/f/radioactivity.htm
[6] http://www.britannica.com/EBchecked/topic/489089/radioactivity