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Protactinium vs Mendelevium

Protactinium
Mendelevium
Mendelevium vs Protactinium


Periodic Table
Symbol
Pa  
Md  
Group Number
3  
15
3  
15
Period Number
7  
7  
Block
f block  
f block  
Element Family
Actinide  
Actinide  
CAS Number
7440133  
99+
7440111  
99+
Space Group Name
I4/mmm  
-  
Space Group Number
139.00  
11
194.00  
7
Facts
Interesting Facts
  • Protactinium metal has 29 isotopes.
  • Isotopes of Protactinium-231 used in nuclear weapon.
  
  • Mendelevium metal is synthetically produced metal.
  • Mendelevium metal has been produced in only trace amount.
  
Sources
Found in Uranium Ores, Mining, Ores of metals  
Bombarding Einsteinium with Helium Ions  
History
  
  
Who Discovered
William Crookes  
Lawrence Berkeley National Laboratory  
Discovery
In 1900  
In 1955  
Abundance
  
  
Abundance In Universe
0.00 %  
17
0.00 %  
40
Abundance In Sun
0.00 %  
26
-  
Abundance In Meteorites
-  
0.00 %  
99+
Abundance In Earth's Crust
0.00 %  
99+
-  
Abundance In Oceans
0.00 %  
99+
-  
Abundance In Humans
0.00 %  
24
0.00 %  
24
Uses
Uses & Benefits
  • Currently known uses of Protactinium metal are limited to research purpose only.
  
  • Currently known uses of Mendelevium metal are limited to research purpose only.
  
Industrial Uses
-  
-  
Medical Uses
-  
-  
Other Uses
-  
-  
Biological Properties
  
  
Toxicity
Highly Toxic  
-  
Present in Human Body
No  
No  
In Blood
0.00 Blood/mg dm-3  
40
0.00 Blood/mg dm-3  
40
In Bone
0.00 p.p.m.  
99+
0.00 p.p.m.  
99+
Physical
Melting Point
1,568.00 °C  
21
827.00 °C  
99+
Boiling Point
4,027.00 °C  
12
0.00 °C  
99+
Appearance
  
  
Physical State
Solid  
Solid  
Color
Silver  
-  
Luster
Metallic  
Metallic  
Hardness
  
  
Mohs Hardness
5.00  
8
-  
Brinell Hardness
125.00 MPa  
99+
350.00 MPa  
36
Vickers Hardness
220.00 MPa  
99+
0.00 MPa  
99+
Speed of Sound
12,400.00 m/s  
3
2,680.00 m/s  
99+
Optical Properties
  
  
Refractive Index
1.60  
33
1.30  
99+
Reflectivity
60.00 %  
23
66.00 %  
17
Allotropes
No  
No  
α Allotropes
-  
-  
β Allotropes
-  
-  
γ Allotropes
-  
-  
Chemical
Chemical Formula
Pa  
Md  
Isotopes
  
  
Known Isotopes
27  
12
16  
23
Electronegativity
  
  
Pauling Electronegativity
1.50  
28
1.30  
33
Sanderson Electronegativity
1.50  
18
1.30  
25
Allred Rochow Electronegativity
1.14  
29
1.20  
28
Mulliken-Jaffe Electronegativity
1.50  
26
1.30  
33
Allen Electronegativity
1.50  
32
1.30  
40
Electropositivity
  
  
Pauling Electropositivity
2.50  
27
2.70  
22
Ionization Energies
  
  
1st Energy Level
568.00 kJ/mol  
99+
635.00 kJ/mol  
99+
2nd Energy Level
1,128.00 kJ/mol  
99+
1,235.00 kJ/mol  
99+
3rd Energy Level
1,814.00 kJ/mol  
99+
2,470.00 kJ/mol  
99+
4th Energy Level
2,991.00 kJ/mol  
99+
3,840.00 kJ/mol  
99+
5th Energy Level
5,120.00 kJ/mol  
99+
6,350.00 kJ/mol  
36
6th Energy Level
5,680.00 kJ/mol  
99+
6,350.00 kJ/mol  
99+
7th Energy level
5,680.00 kJ/mol  
99+
6,350.00 kJ/mol  
99+
8th Energy Level
5,680.00 kJ/mol  
99+
6,350.00 kJ/mol  
99+
9th Energy Level
5,120.00 kJ/mol  
99+
6,350.00 kJ/mol  
99+
10th Energy Level
5,120.00 kJ/mol  
99+
6,350.00 kJ/mol  
99+
11th Energy Level
5,680.00 kJ/mol  
99+
6,400.00 kJ/mol  
99+
12th Energy Level
5,680.00 kJ/mol  
99+
60,100.00 kJ/mol  
16
13th Energy Level
5,680.00 kJ/mol  
99+
6,350.00 kJ/mol  
37
14th Energy Level
5,680.00 kJ/mol  
99+
1,150.00 kJ/mol  
99+
15th Energy Level
56,800.00 kJ/mol  
99+
63,500.00 kJ/mol  
37
16th Energy Level
56,800.00 kJ/mol  
99+
635.00 kJ/mol  
99+
17th Energy Level
568.50 kJ/mol  
99+
1,107.00 kJ/mol  
21
18th Energy Level
5,680.00 kJ/mol  
99+
6,350.00 kJ/mol  
39
19th Energy Level
568.30 kJ/mol  
99+
635.00 kJ/mol  
99+
20th Energy Level
568.00 kJ/mol  
99+
635.00 kJ/mol  
40
21st Energy Level
568.00 kJ/mol  
99+
6,350.00 kJ/mol  
13
22nd Energy Level
568.00 kJ/mol  
99+
635.00 kJ/mol  
34
23rd Energy Level
568.00 kJ/mol  
99+
6,350.00 kJ/mol  
13
24th Energy Level
568.00 kJ/mol  
99+
635.00 kJ/mol  
36
25th Energy Level
568.00 kJ/mol  
99+
635.00 kJ/mol  
38
26th Energy Level
568.00 kJ/mol  
99+
635.00 kJ/mol  
37
27th Energy Level
568.00 kJ/mol  
99+
635.00 kJ/mol  
39
28th Energy Level
568.00 kJ/mol  
99+
635.00 kJ/mol  
99+
29th Energy Level
568.00 kJ/mol  
99+
635.00 kJ/mol  
99+
30th Energy Level
568.00 kJ/mol  
99+
635.00 kJ/mol  
40
Electrochemical Equivalent
1.72 g/amp-hr  
99+
3.21 g/amp-hr  
13
Electron Work Function
5.89 eV  
3
3.89 eV  
37
Other Chemical Properties
Ionization, Radioactive Isotopes, Radioactivity  
Ionization, Radioactive Isotopes, Radioactivity  
Atomic
Atomic Number
91  
27
101  
17
Electron Configuration
[Rn] 5f2 6d1 7s2  
[Rn] 5f13 7s2  
Crystal Structure
Tetragonal (TETR)  
Not Known  
Crystal Lattice
TETR-Crystal-Structure-of-Protactinium.jpg#100  
Unknown-Crystal-Structure-of-Mendelevium.jpg#100  
Atom
  
  
Number of Protons
91  
27
101  
17
Number of Neutrons
122  
22
157  
8
Number of Electrons
91  
27
101  
17
Radius of an Atom
  
  
Atomic Radius
163.00 pm  
27
175.00 pm  
21
Covalent Radius
200.00 pm  
11
175.00 pm  
25
Van der Waals Radius
243.00 pm  
15
246.00 pm  
12
Atomic Weight
231.04 amu  
24
258.00 amu  
14
Atomic Volume
15.00 cm3/mol  
99+
19.90 cm3/mol  
32
Adjacent Atomic Numbers
  
  
Previous Element
Thorium
  
Fermium
  
Next Element
Uranium
  
Nobelium
  
Valence Electron Potential
92.00 (-eV)  
11
63.70 (-eV)  
23
Lattice Constant
392.50 pm  
26
-  
Lattice Angles
π/2, π/2, π/2  
-  
Lattice C/A Ratio
1.58  
36
1.58  
36
Mechanical
Density
  
  
Density At Room Temperature
15.37 g/cm3  
20
10.30 g/cm3  
38
Density When Liquid (at m.p.)
15.37 g/cm3  
21
10.30 g/cm3  
39
Tensile Strength
80.00 MPa  
29
80.00 MPa  
29
Viscosity
0.00  
25
0.00  
25
Vapor Pressure
  
  
Vapor Pressure at 1000 K
0.00 (Pa)  
37
0.00 (Pa)  
37
Vapor Pressure at 2000 K
0.00 (Pa)  
32
0.00 (Pa)  
37
Elasticity properties
  
  
Shear Modulus
16.00 GPa  
99+
32.00 GPa  
24
Bulk Modulus
47.00 GPa  
26
0.00 GPa  
99+
Young's Modulus
47.00 GPa  
99+
12.00 GPa  
99+
Poisson Ratio
0.23  
30
0.30  
14
Other Mechanical Properties
-  
-  
Magnetic
Magnetic Characteristics
  
  
Specific Gravity
15.37  
23
13.50  
29
Magnetic Ordering
Paramagnetic  
-  
Permeability
0.00 H/m  
10
0.00 H/m  
11
Susceptibility
0.00  
21
0.00  
24
Electrical Properties
  
  
Electrical Property
Conductor  
-  
Resistivity
177.00 nΩ·m  
21
0.63 nΩ·m  
99+
Electrical Conductivity
0.05 106/cm Ω  
39
0.00 106/cm Ω  
99+
Electron Affinity
53.03 kJ/mol  
22
50.00 kJ/mol  
26
Thermal
Specific Heat
0.12 J/(kg K)  
99+
0.10 J/(kg K)  
99+
Molar Heat Capacity
27.20 J/mol·K  
24
27.00 J/mol·K  
29
Thermal Conductivity
47.00 W/m·K  
32
0.00 W/m·K  
99+
Critical Temperature
1,841.00 K  
25
1,100.00 K  
99+
Thermal Expansion
9.90 µm/(m·K)  
99+
11.60 µm/(m·K)  
99+
Enthalpy
  
  
Enthalpy of Vaporization
481.00 kJ/mol  
17
380.50 kJ/mol  
26
Enthalpy of Fusion
12.34 kJ/mol  
34
-  
Enthalpy of Atomization
481.90 kJ/mol  
19
410.80 kJ/mol  
25
Standard Molar Entropy
198.10 J/mol.K  
1
37.40 J/mol.K  
99+
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