Here's a new video about Protactinium, number 91 on the periodic table! Videos on all 118 elements: http://bit.ly/118elements Eric Scerri's book (UK): http://bit.ly/SevenScerriUK And (US): http://bit.ly/SevenScerriUS (*) Isotope 238 has half life 6.8 hrs Isotope 238m has half life 1.17 mins More chemistry at http://www.periodicvideos.com/ Follow us on Facebook at http://www.facebook.com/periodicvideos And on Twitter at http://twitter.com/periodicvideos From the School of Chemistry at The University of Nottingham: http://bit.ly/NottChem Periodic Videos films are by video journalist Brady Haran: http://www.bradyharan.com/ A run-down of Brady's channels: http://bit.ly/bradychannels