Period 1 Period 2 Period 3 Period 4 Period 5 Period 6 The S Orbital The P Orbital The D Orbital The F Orbital Transition Elements Lanthanide Series Actinide Series Multivalence1 Multivalence2 Rota Period I II III IV V VI VII VIII 1+ 2+ 3+ 4+ 5+ 6+ 7+ 8+ 3- 2- 1- 0 H He Li Be B C N O F Ne Na Mg Al Si P S Cl Ar K Ca Sc Ti V Cr Mn * * * Fe Co Ni Cu Zn Ga Ge As Se Br Kr Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe Cs Ba La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn Fr Ra Ac Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr Rf Db The Shovel About the Rota Period Rota Period Explained (pdf) Rota Period Abstract Published in JSE (pdf) Rota Period Published in the Journal of Science Education (pdf) How the Rota Period Handles Some Periodic Table Anomalies (pdf) Atomic Radius, Electronegativity, Electropositivity, First Ionization Energy, Mass + Z, Metallic Properties and Oxidation State Trends Contact me Links *** Iron (Fe) is an example of how multi valence elements are displayed. © 2007 James L. Rota, Rotaperiod.com

Pr - Praseodymium Atomic Number: 59 Atomic Weight (Mass): 140.90770 Melting Point: 1100 °C Boiling Point: 3000 °C Orbital Class: 4f Orbital: [Xe] 4f3 6s2 Class: Lanthanides Electronegativity: 1.1 Density: 6.8 g.cm-3 Van der Waals Radius: unknown Ionic Radius: 0.101 nm (+3) First Ionization Energy: 527.20 kJ mol-1 Second Ionization Energy: 1017.93 kJ mol-1 Third Ionization Energy: 2086.41 kJ mol-1 Heat of Fusion: 11.3 kJ mol-1 Heat of Vaporization: 357 kJ mol-1 Heat of Atomization: 356.69 kJ mol-1 Electrical Conductivity: 68 µ Ωcm Thermal Conductivity: 12.5 W m-1 K-1 Related To: C, Si, Ti, Ge, Zr, Pd, Sn, Ce, Pr, Tb, Hf, Pt, Pb, Th, Bk, Rf, Valences I II III IV V VI VII VIII 1+ 2+ 3+ 4+ 5+ 6+ 7+ 8+ 3- 2- 1- 0 * Pr * Praseodymium resembles the typical trivalent rare earths, however, it will exhibit a +4 state when stabilized in a zirconia host. The element is found in most all light rare earth derivatives. It is highly valued in glass and ceramic production as a bright yellow pigment because of its optimum reflectance at 560 nm. Much research is being done on its optical properties for use in amplification of telecommunication systems, including as a doping agent in fluoride fibers. Praseodymium doped zirconia is a potential cathode for low temperature Solid Oxide Fuel Cell applications. It is also used in the scintillator for medical CAT scans. Praseodymium is a Block F, Group 3, Period 6 element. The electronic configuration is [Xe] 4f3 6s2. In its elemental form praseodymium's CAS number is 7440-10-0. The praseodymium atom has a radius of 182.pm and it's Van der Waals radius is is unknown. Praseodymium was first discovered by von Welsbach in 1885. French:praseodyme, German: Praseodym, Italian:praseodimio, Portuguese: Prosedimio, Spanish:praseodimio, Swedish: Praseodym This element can be purchased in a variety of forms including as metal, compounds, ultra high purity, nanoparticles, and isotopes at www.americanelements.com Source: www.americanelements.com ####### Praseodymium is a chemical element in the periodic table that has the symbol Pr and atomic number 59. Praseodymium is a soft silvery metallic element, and belongs to the lanthanide group. It is somewhat more resistant to corrosion in air than europium, lanthanum, cerium, or neodymium, but it does develop a green oxide coating that spalls off when exposed to air, exposing more metal to oxidation. For this reason, praseodymium should be stored under a light mineral oil or sealed in glass. Source: Wikipedia.org Home © 2007 Rotaperiod.com