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Neptunium vs Mendelevium

Neptunium
Mendelevium
Mendelevium vs Neptunium


Periodic Table
Symbol
Np  
Md  
Group Number
3  
15
3  
15
Period Number
7  
7  
Block
f block  
f block  
Element Family
Actinide  
Actinide  
CAS Number
7439998  
99+
7440111  
99+
Space Group Name
Pnma  
-  
Space Group Number
62.00  
14
194.00  
7
Facts
Interesting Facts
Neptunium was the first transuranium element to be discovered.  
  • Mendelevium metal is synthetically produced metal.
  • Mendelevium metal has been produced in only trace amount.
  
Sources
Made by Bombarding Uranium with Neutrons, Ores of metals  
Bombarding Einsteinium with Helium Ions  
History
  
  
Who Discovered
Edwin McMillan and Philip H. Abelson  
Lawrence Berkeley National Laboratory  
Discovery
In 1940  
In 1955  
Abundance
  
  
Abundance In Universe
0.00 %  
40
0.00 %  
40
Abundance In Sun
0.00 %  
26
-  
Abundance In Meteorites
0.00 %  
99+
0.00 %  
99+
Abundance In Earth's Crust
0.00 %  
99+
-  
Abundance In Oceans
-  
-  
Abundance In Humans
0.00 %  
24
0.00 %  
24
Uses
Uses & Benefits
  • Currently known uses of Neptunium metal are limited to research purpose only.
  • Neptunium’s isotope neptunium-237 is used as a neutron detectors.
  
  • Currently known uses of Mendelevium metal are limited to research purpose only.
  
Industrial Uses
-  
-  
Medical Uses
-  
-  
Other Uses
Alloys, Nuclear Research, Research Purposes  
-  
Biological Properties
  
  
Toxicity
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
640.00 °C  
99+
827.00 °C  
99+
Boiling Point
3,902.00 °C  
13
0.00 °C  
99+
Appearance
  
  
Physical State
Solid  
Solid  
Color
Silver  
-  
Luster
Metallic  
Metallic  
Hardness
  
  
Mohs Hardness
6.00  
6
-  
Brinell Hardness
622.00 MPa  
23
350.00 MPa  
36
Vickers Hardness
640.00 MPa  
23
0.00 MPa  
99+
Speed of Sound
2,260.00 m/s  
99+
2,680.00 m/s  
99+
Optical Properties
  
  
Refractive Index
1.30  
99+
1.30  
99+
Reflectivity
64.00 %  
19
66.00 %  
17
Allotropes
No  
No  
α Allotropes
-  
-  
β Allotropes
-  
-  
γ Allotropes
-  
-  
Chemical
Chemical Formula
Np  
Md  
Isotopes
  
  
Known Isotopes
20  
19
16  
23
Electronegativity
  
  
Pauling Electronegativity
1.36  
30
1.30  
33
Sanderson Electronegativity
1.36  
23
1.30  
25
Allred Rochow Electronegativity
1.22  
27
1.20  
28
Mulliken-Jaffe Electronegativity
1.36  
31
1.30  
33
Allen Electronegativity
1.36  
37
1.30  
40
Electropositivity
  
  
Pauling Electropositivity
2.64  
25
2.70  
22
Ionization Energies
  
  
1st Energy Level
604.50 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
1,997.00 kJ/mol  
99+
2,470.00 kJ/mol  
99+
4th Energy Level
3,242.00 kJ/mol  
99+
3,840.00 kJ/mol  
99+
5th Energy Level
6,180.00 kJ/mol  
99+
6,350.00 kJ/mol  
36
6th Energy Level
5,785.00 kJ/mol  
99+
6,350.00 kJ/mol  
99+
7th Energy level
6,040.00 kJ/mol  
99+
6,350.00 kJ/mol  
99+
8th Energy Level
6,040.00 kJ/mol  
99+
6,350.00 kJ/mol  
99+
9th Energy Level
6,180.00 kJ/mol  
99+
6,350.00 kJ/mol  
99+
10th Energy Level
6,180.00 kJ/mol  
99+
6,350.00 kJ/mol  
99+
11th Energy Level
6,180.00 kJ/mol  
99+
6,400.00 kJ/mol  
99+
12th Energy Level
61,800.00 kJ/mol  
13
60,100.00 kJ/mol  
16
13th Energy Level
6,180.00 kJ/mol  
40
6,350.00 kJ/mol  
37
14th Energy Level
6,180.00 kJ/mol  
29
1,150.00 kJ/mol  
99+
15th Energy Level
60,600.00 kJ/mol  
99+
63,500.00 kJ/mol  
37
16th Energy Level
60,420.00 kJ/mol  
31
635.00 kJ/mol  
99+
17th Energy Level
604.00 kJ/mol  
99+
1,107.00 kJ/mol  
21
18th Energy Level
6,040.00 kJ/mol  
99+
6,350.00 kJ/mol  
39
19th Energy Level
604.50 kJ/mol  
99+
635.00 kJ/mol  
99+
20th Energy Level
604.00 kJ/mol  
99+
635.00 kJ/mol  
40
21st Energy Level
6,040.00 kJ/mol  
17
6,350.00 kJ/mol  
13
22nd Energy Level
604.00 kJ/mol  
40
635.00 kJ/mol  
34
23rd Energy Level
6,040.00 kJ/mol  
18
6,350.00 kJ/mol  
13
24th Energy Level
604.50 kJ/mol  
99+
635.00 kJ/mol  
36
25th Energy Level
604.00 kJ/mol  
99+
635.00 kJ/mol  
38
26th Energy Level
604.00 kJ/mol  
99+
635.00 kJ/mol  
37
27th Energy Level
604.00 kJ/mol  
99+
635.00 kJ/mol  
39
28th Energy Level
604.00 kJ/mol  
99+
635.00 kJ/mol  
99+
29th Energy Level
604.00 kJ/mol  
99+
635.00 kJ/mol  
99+
30th Energy Level
604.00 kJ/mol  
99+
635.00 kJ/mol  
40
Electrochemical Equivalent
1.77 g/amp-hr  
99+
3.21 g/amp-hr  
13
Electron Work Function
4.90 eV  
12
3.89 eV  
37
Other Chemical Properties
Ionization, Radioactive Isotopes, Radioactivity, Solubility  
Ionization, Radioactive Isotopes, Radioactivity  
Atomic
Atomic Number
93  
25
101  
17
Electron Configuration
[Rn] 5f4 6d1 7s2  
[Rn] 5f13 7s2  
Crystal Structure
Orthorhombic (ORTH)  
Not Known  
Crystal Lattice
ORTH-Crystal-Structure-of-Neptunium.jpg#100  
Unknown-Crystal-Structure-of-Mendelevium.jpg#100  
Atom
  
  
Number of Protons
93  
25
101  
17
Number of Neutrons
144  
15
157  
8
Number of Electrons
93  
25
101  
17
Radius of an Atom
  
  
Atomic Radius
155.00 pm  
32
175.00 pm  
21
Covalent Radius
190.00 pm  
18
175.00 pm  
25
Van der Waals Radius
221.00 pm  
27
246.00 pm  
12
Atomic Weight
237.00 amu  
22
258.00 amu  
14
Atomic Volume
11.62 cm3/mol  
99+
19.90 cm3/mol  
32
Adjacent Atomic Numbers
  
  
Previous Element
Uranium
  
Fermium
  
Next Element
Plutonium
  
Nobelium
  
Valence Electron Potential
96.00 (-eV)  
9
63.70 (-eV)  
23
Lattice Constant
666.30 pm  
3
-  
Lattice Angles
π/2, π/2, π/2  
-  
Lattice C/A Ratio
1.43  
99+
1.58  
36
Mechanical
Density
  
  
Density At Room Temperature
19.38 g/cm3  
14
10.30 g/cm3  
38
Density When Liquid (at m.p.)
20.25 g/cm3  
10
10.30 g/cm3  
39
Tensile Strength
125.00 MPa  
26
80.00 MPa  
29
Viscosity
0.00  
25
0.00  
25
Vapor Pressure
  
  
Vapor Pressure at 1000 K
0.00 (Pa)  
22
0.00 (Pa)  
37
Vapor Pressure at 2000 K
0.11 (Pa)  
17
0.00 (Pa)  
37
Elasticity properties
  
  
Shear Modulus
5.60 GPa  
99+
32.00 GPa  
24
Bulk Modulus
180.00 GPa  
9
0.00 GPa  
99+
Young's Modulus
46.00 GPa  
99+
12.00 GPa  
99+
Poisson Ratio
0.26  
22
0.30  
14
Other Mechanical Properties
Ductile  
-  
Magnetic
Magnetic Characteristics
  
  
Specific Gravity
20.25  
15
13.50  
29
Magnetic Ordering
Paramagnetic  
-  
Permeability
0.00 H/m  
6
0.00 H/m  
11
Susceptibility
0.00  
24
0.00  
24
Electrical Properties
  
  
Electrical Property
Conductor  
-  
Resistivity
1.22 nΩ·m  
99+
0.63 nΩ·m  
99+
Electrical Conductivity
0.01 106/cm Ω  
99+
0.00 106/cm Ω  
99+
Electron Affinity
118.60 kJ/mol  
6
50.00 kJ/mol  
26
Thermal
Specific Heat
0.12 J/(kg K)  
99+
0.10 J/(kg K)  
99+
Molar Heat Capacity
29.46 J/mol·K  
10
27.00 J/mol·K  
29
Thermal Conductivity
6.30 W/m·K  
99+
0.00 W/m·K  
99+
Critical Temperature
913.00 K  
99+
1,100.00 K  
99+
Thermal Expansion
13.30 µm/(m·K)  
35
11.60 µm/(m·K)  
99+
Enthalpy
  
  
Enthalpy of Vaporization
336.00 kJ/mol  
39
380.50 kJ/mol  
26
Enthalpy of Fusion
3.20 kJ/mol  
99+
-  
Enthalpy of Atomization
275.30 kJ/mol  
99+
410.80 kJ/mol  
25
Standard Molar Entropy
64.00 J/mol.K  
21
37.40 J/mol.K  
99+
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