Protactinium




 * Name:** Protactinium
 * Symbol:** Pa
 * Atomic Number:** 91 **Atomic Mass:** 231.03587 amu
 * Melting Point:** 1600.0 °C
 * Boiling Point:** Unknown
 * Number of Protons/Electrons:** 91
 * Number of Neutrons:** 140
 * Classification:** Rare
 * Period:** 7
 * Group #:** 6
 * State At Room Temp.:** Solid medium

I did the 2 pics, bohr model and area -231 and could possibly sustain a nuclear chain reaction! http://www.chemicalelements.com/elements/pa.html

Protactinium was first identified by Kasimir Fajans and O.H. Göhring in 1913 while studying [|uranium's] decay chain. The particular [|isotope] they found, protactinium-234m, has a half-life of about 1.17 minutes. They named the element brevium, meaning brief, and then continued with their studies. Protactinium's existence was confirmed in 1918 when another isotope, protactinium-231, was independently discovered and studied by two groups of scientists, Otto Hahn and Lise Meitner of Germany and Frederick Soddy and John Cranston of Great Britain. Protactinium was first isolated by Aristid V. Grosse in 1934.
 * History**


 * Other Information**

In 1959 and 1961, it was announced that the Great Britain Atomic Energy Authority extracted by a 12-stage process 125 g of 99.9% protactinium, the world's only stock of the metal for many years to come. The extraction was made from 60 tons of waste material at a cost of about $500,000. Protactinium is one of the rarest and most expensive naturally occurring elements.

Costs

 * O.R.N.L. supplies promethium-231 at a cost of about $280/g.**

Hazards
In 1959 and 1961, it was announced that the Great Britain Atomic Energy Authority extracted by a 12-stage process 125 g of 99.9% protactinium, the world's only stock of the metal for many years to come. The extraction was made from 60 tons of waste material at a cost of about $500,000. Protactinium is one of the rarest and most expensive naturally occurring elements.
 * The elements is an alpha emitter (5.0 MeV) and is a radiological hazard similar to polonium.**


 * Video

http://www.teachertube.com/v.php?viewkey=532b6122d0b505dc3020**