protactinium

A more stable isotope of protactinium was discovered in 1918, and therefore the name was changed to protoactinium and then to protactinium in 1949. Symbol PA
 * Definition** : protaction #91


 * Density;** 15.37g cm-3
 * Boiling/condensation point:** 4300k,4027f, 7280f
 * Heat of vaporization:** 12.34kj mol
 * Freezing/ Melting point:** 1841k, 15.68c, 2854F
 * Heat of Fusion;** 481kj
 * Details:**
 * PaO2** — Partial pressure of oxygen at sea level (765 mmHg) in arterial blood is between 75 mmHg and 100 mmHg[|[][|4][|]][|[][|5][|]][|[][|6][|]].

Information: A **chemical element** is a pure [|chemical substance] consisting of one type of [|atom] distinguished by its [|atomic number], which is the number of [|protons] in its [|nucleus].[|[][|1][|]] Familiar examples of elements include [|carbon], [|oxygen], [|aluminum], [|iron], [|copper], [|gold], [|mercury], and [|lead]. Standard atomic mass: 231.03588(2) [|u]
 * [|Protactinium]** (**Pa**) has no stable isotopes. There are three naturally occurring isotopes, allowing a standard mass to be given.