Symbol
Pa
  
No
  
Group Number
Not Available
  
Not Available
  
Period Number
7
  
7
  
Block
f block
  
f block
  
Element Family
Actinide
  
Actinide
  
Space Group Name
I4/mmm
  
Not Available
  
Space Group Number
Not Available
  
Interesting Facts
- Protactinium metal has 29 isotopes.
- Isotopes of Protactinium-231 used in nuclear weapon.
  
- The most stable isotope of Nobelium metal is No-259.
- No-259 has a half-life of fifty-eight minutes.
  
Sources
Found in Uranium Ores, Mining, Ores of metals
  
Bombarding Curium-246 or Curium-249 with Carbon-12 Nuclei, Found in Minerals, Mining
  
History
  
  
Who Discovered
William Crookes
  
Joint Institute for Nuclear Research
  
Discovery
In 1900
  
In 1966
  
Abundance
  
  
Abundance In Earth's Crust
Not Available
  
Abundance In Oceans
Not Available
  
Uses & Benefits
- Currently known uses of Protactinium metal are limited to research purpose only.
  
- Currently known uses of Nobelium metal are limited to research purpose only.
  
Industrial Uses
NA
  
NA
  
Medical Uses
NA
  
NA
  
Other Uses
NA
  
Research Purposes
  
Biological Properties
  
  
Toxicity
Highly Toxic
  
Unknown
  
Present in Human Body
No
  
No
  
In Blood
0.00 Blood/mg dm-3
  
37
0.00 Blood/mg dm-3
  
37
In Bone
0.00 p.p.m.
  
36
0.00 p.p.m.
  
36
Melting Point
1,568.00 °C
  
21
Boiling Point
4,027.00 °C
  
12
Not Available
  
Appearance
  
  
Physical State
Solid
  
Solid
  
Color
Silver
  
Unknown
  
Luster
Metallic
  
Unknown Luster
  
Hardness
  
  
Speed of Sound
Not Available
  
Not Available
  
Optical Properties
  
  
Allotropes
No
  
No
  
α Allotropes
Not Available
  
Not Available
  
β Allotropes
Not Available
  
Not Available
  
γ Allotropes
Not Available
  
Not Available
  
Chemical Formula
Pa
  
No
  
Isotopes
  
  
Electronegativity
  
  
Pauling Electronegativity
Allred Rochow Electronegativity
Electropositivity
  
  
Pauling Electropositivity
Ionization Energies
  
  
1st Energy Level
568.00 kJ/mol
  
99+
642.00 kJ/mol
  
99+
2nd Energy Level
1,128.00 kJ/mol
  
99+
1,254.00 kJ/mol
  
99+
3rd Energy Level
1,814.00 kJ/mol
  
99+
2,643.00 kJ/mol
  
99+
4th Energy Level
2,991.00 kJ/mol
  
99+
3,956.00 kJ/mol
  
39
Electrochemical Equivalent
1.72 g/amp-hr
  
99+
4.83 g/amp-hr
  
4
Electron Work Function
Not Available
  
Not Available
  
Other Chemical Properties
Ionization, Radioactive Isotopes, Radioactivity
  
Ionization, Radioactive Isotopes, Radioactivity
  
Electron Configuration
[Rn] 5f2 6d1 7s2
  
[Rn] 5f14 7s2
  
Crystal Structure
Tetragonal (TETR)
  
Not Known
  
Crystal Lattice
TETR-Crystal-Structure-of-Protactinium.jpg#100
  
Unknown-Crystal-Structure-of-Nobelium.jpg#100
  
Atom
  
  
Radius of an Atom
  
  
Atomic Radius
Not Available
  
Covalent Radius
Not Available
  
Atomic Volume
15.00 cm3/mol
  
34
Not Available
  
Adjacent Atomic Numbers
  
  
Valence Electron Potential
92.00 (-eV)
  
11
26.00 (-eV)
  
99+
Lattice Constant
Not Available
  
Lattice Angles
π/2, π/2, π/2
  
NA
  
Lattice C/A Ratio
Not Available
  
Not Available
  
Density
  
  
Density At Room Temperature
15.37 g/cm
3
  
20
Not Available
  
Tensile Strength
Not Available
  
Not Available
  
Viscosity
Not Available
  
Not Available
  
Vapor Pressure
  
  
Elasticity properties
  
  
Poisson Ratio
Not Available
  
Not Available
  
Other Mechanical Properties
Unknown
  
Unknown
  
Magnetic Characteristics
  
  
Specific Gravity
Not Available
  
Magnetic Ordering
Paramagnetic
  
Unknown
  
Electrical Properties
  
  
Electrical Property
Conductor
  
Unknown
  
Resistivity
177.00 nΩ·m
  
21
Not Available
  
Electrical Conductivity
0.05 10
6/cm Ω
  
34
Not Available
  
Specific Heat
0.12 J/(kg K)
  
40
Not Available
  
Molar Heat Capacity
Not Available
  
Not Available
  
Thermal Conductivity
47.00 W/m·K
  
32
Not Available
  
Critical Temperature
Not Available
  
Not Available
  
Thermal Expansion
9.90 µm/(m·K)
  
40
Not Available
  
Enthalpy
  
  
Enthalpy of Fusion
12.34 kJ/mol
  
28
Not Available
  
Standard Molar Entropy
198.10 J/mol.K
  
1
Not Available