Symbol
Pa
  
Sr
  
Group Number
Not Available
  
Period Number
7
  
5
  
Block
f block
  
s block
  
Element Family
Actinide
  
Alkaline Earth
  
Space Group Name
I4/mmm
  
Fm_ 3m
  
Interesting Facts
- Protactinium metal has 29 isotopes.
- Isotopes of Protactinium-231 used in nuclear weapon.
  
- Strontium element is softer than Calcium.
- Silvery Strontium turns yellow, if exposed to air.
  
Sources
Found in Uranium Ores, Mining, Ores of metals
  
Found in Minerals, Mining, Ores of Minerals
  
History
  
  
Who Discovered
William Crookes
  
William Cruickshank
  
Discovery
In 1900
  
In 1787
  
Abundance
  
  
Abundance In Universe
Not Available
  
Abundance In Sun
~-9999 %
  
~0.000005 %
  
15
Abundance In Meteorites
Not Available
  
Abundance In Earth's Crust
Abundance In Humans
Not Available
  
Uses & Benefits
- Currently known uses of Protactinium metal are limited to research purpose only.
  
- Strontium metal is used to producing ferrite magnets as well as refining zinc.
-
By-product of nuclear reactors called Strontium-90 is a radioactive isotope; it is absorbed by tissues and destroys bone marrow and cancer growth.
  
Industrial Uses
NA
  
Ammunition Industry, Chemical Industry
  
Medical Uses
NA
  
NA
  
Other Uses
NA
  
Alloys
  
Biological Properties
  
  
Toxicity
Highly Toxic
  
Non Toxic
  
Present in Human Body
No
  
Yes
  
In Blood
0.00 Blood/mg dm-3
  
37
0.03 Blood/mg dm-3
  
19
In Bone
0.00 p.p.m.
  
36
140.00 p.p.m.
  
7
Melting Point
1,568.00 °C
  
21
Boiling Point
4,027.00 °C
  
12
1,384.00 °C
  
99+
Appearance
  
  
Physical State
Solid
  
Solid
  
Color
Silver
  
Silvery White
  
Luster
Metallic
  
Metallic
  
Hardness
  
  
Mohs Hardness
Not Available
  
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
  
Sr
  
Isotopes
  
  
Electronegativity
  
  
Pauling Electronegativity
Sanderson Electronegativity
Not Available
  
Allred Rochow Electronegativity
Mulliken-Jaffe Electronegativity
Not Available
  
Allen Electronegativity
Not Available
  
Electropositivity
  
  
Pauling Electropositivity
Ionization Energies
  
  
1st Energy Level
568.00 kJ/mol
  
99+
549.50 kJ/mol
  
99+
2nd Energy Level
1,128.00 kJ/mol
  
99+
1,064.20 kJ/mol
  
99+
3rd Energy Level
1,814.00 kJ/mol
  
99+
4,138.00 kJ/mol
  
10
4th Energy Level
2,991.00 kJ/mol
  
99+
5,500.00 kJ/mol
  
13
5th Energy Level
Not Available
  
6,910.00 kJ/mol
  
18
6th Energy Level
Not Available
  
8,760.00 kJ/mol
  
18
7th Energy level
Not Available
  
10,230.00 kJ/mol
  
19
8th Energy Level
Not Available
  
11,800.00 kJ/mol
  
19
9th Energy Level
Not Available
  
15,600.00 kJ/mol
  
17
10th Energy Level
Not Available
  
17,100.00 kJ/mol
  
19
11th Energy Level
Not Available
  
31,270.00 kJ/mol
  
6
Electrochemical Equivalent
1.72 g/amp-hr
  
99+
1.64 g/amp-hr
  
99+
Electron Work Function
Not Available
  
Other Chemical Properties
Ionization, Radioactive Isotopes, Radioactivity
  
Ionization, Radioactive Isotopes, Radioactivity, Solubility
  
Electron Configuration
[Rn] 5f2 6d1 7s2
  
[Kr] 5s2
  
Crystal Structure
Tetragonal (TETR)
  
Face Centered Cubic (FCC)
  
Crystal Lattice
TETR-Crystal-Structure-of-Protactinium.jpg#100
  
FCC-Crystal-Structure-of-Strontium.jpg#100
  
Atom
  
  
Radius of an Atom
  
  
Atomic Volume
15.00 cm3/mol
  
34
33.70 cm3/mol
  
6
Adjacent Atomic Numbers
  
  
Valence Electron Potential
92.00 (-eV)
  
11
25.70 (-eV)
  
99+
Lattice Angles
π/2, π/2, π/2
  
π/2, π/2, π/2
  
Lattice C/A Ratio
Not Available
  
Not Available
  
Density
  
  
Density At Room Temperature
15.37 g/cm3
  
20
2.64 g/cm3
  
99+
Density When Liquid (at m.p.)
Not Available
  
2.38 g/cm3
  
99+
Tensile Strength
Not Available
  
Not Available
  
Viscosity
Not Available
  
Not Available
  
Vapor Pressure
  
  
Vapor Pressure at 1000 K
Not Available
  
Elasticity properties
  
  
Shear Modulus
Not Available
  
Young's Modulus
Not Available
  
Poisson Ratio
Not Available
  
Other Mechanical Properties
Unknown
  
NA
  
Magnetic Characteristics
  
  
Magnetic Ordering
Paramagnetic
  
Paramagnetic
  
Electrical Properties
  
  
Electrical Property
Conductor
  
NA
  
Resistivity
177.00 nΩ·m
  
21
132.00 nΩ·m
  
24
Electrical Conductivity
0.05 106/cm Ω
  
34
0.08 106/cm Ω
  
26
Electron Affinity
Not Available
  
5.03 kJ/mol
  
38
Specific Heat
0.12 J/(kg K)
  
40
0.30 J/(kg K)
  
18
Molar Heat Capacity
Not Available
  
26.40 J/mol·K
  
28
Thermal Conductivity
47.00 W/m·K
  
32
35.40 W/m·K
  
37
Critical Temperature
Not Available
  
Not Available
  
Thermal Expansion
9.90 µm/(m·K)
  
40
22.50 µm/(m·K)
  
18
Enthalpy
  
  
Enthalpy of Vaporization
Not Available
  
150.00 kJ/mol
  
99+
Enthalpy of Fusion
12.34 kJ/mol
  
28
9.16 kJ/mol
  
38
Enthalpy of Atomization
Not Available
  
163.20 kJ/mol
  
99+
Standard Molar Entropy
198.10 J/mol.K
  
1
55.00 J/mol.K
  
26