Elements
91

Pa

Protactinium

Protactinium (Pa) is a shiny silver colored radioactive metal that has the atomic number 91 in the periodic table. It is an Actinoid Metal with the symbol Pa.

Protactinium is found mainly in uranium deposits and is highly radioactive and toxic. It does not have many commercial uses due to its instability but is mainly used in research science. It is a by product of nuclear fuel and can be obtained from nuclear fuel rods. It was first identified in 1913 by Kasimir Fajans and Oswald Helmuth Göhring and was given the name brevium due to its short half life. It was not until 1917 that a more stable isotope was found and it was renamed protactinium. Protactinium is one of the rarest and most expensive naturally occurring element and is found in the ore pitchblende. It can also be produced in nuclear reactors and having a half life of 32,760 years means as waste it needs carefully disposing. Whilst not commercially used it has some use in the dating of ice age glaciers due to its long half life. It is a solid metal at room temperature and it has a melting point of 1568°c and a boiling point of 4027°c.

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FAQ's

What is the Melting Point for Protactinium?

Protactinium has a Melting Point of 1600°F, meaning at 1600°F it will turn to a liquid.

What is the Boiling Point for Protactinium?

Protactinium has a Boiling Point of 4000°F, meaning at 4000°F it will turn to a Gas.

What is the Electronegativity of Protactinium?

Protactinium's Electronegativty is 1.5. Electronegativity is a measure of how strongly atoms attract bonding electrons to themselves.

What is the Heat of Vaporization of Protactinium?

Protactinium has a Heat of Vaporization of kJ/mol.

Uses

It has no significant commercial applications.

Sources

Does not occur in nature. Found among fission products of uranium, thorium, and plutonium.

91
Protons
91
Electrons
140
Neutrons

Pa

Element Symbol
Pa
Atomic Weight
231.036
Atomic Number
91
State
Solid
Melting Point
Unknown
1600
°C
Boiling Point
4000
Unknown
°C
Heat of Vaporization
Unknown
kJ/mol
Crystal Structure
Orthorhombic
Thermoconductivity
0.47
Unknown
W/cmK
Shells
2,8,18,32,20,9,2
Group
Actinide
Period
7
Block
F Block
Orbitals
[Rn] 5f2 6d1 7s2
Coefficient of Thermal Expansion
9.7 10^-6 K^-1
Covalent Radius
--
Density at 293K
15.4 g/cm³
Electrical Conductivity
0.0529 10^6/cm ohm
First Ionization Potential
5.89 V
Second Ionization Potential
--
Third Ionization Potential
--
Ionic Radius
--
Oxydation States
(5),4
Lattice Parameter
3.925 Å
Lattice Parameter 2
--
Lattice Parameter 3
10.963 Å
Pronounced

PRO-tak-tin-eh-em

Discovered by

Fredrich Soddy, John Cranston, Otto Hahn, Lise Meitner

Discovery date

1917

Orbital configuration
2,8,18,32,20,9,2

Download the Periodic Table

Explore Other Actinides

238.029
92

U

Uranium
258
101

Md

Mendelevium
251
98

Cf

Californium
244
94

Pu

Plutonium
243
95

Am

Americium
237
93

Np

Neptunium
227
89

Ac

Actinium
232.038
90

Th

Thorium
259
102

No

Nobelium
262
103

Lr

Lawrencium
257
100

Fm

Fermium
247
96

Cm

Curium
247
97

Bk

Berkelium
252
99

Es

Einsteinium
The actinide series contains 15 metallic elements from number 89 (actinium) to 103 (lawrencium). They are located in group 3 in the periodic table.
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