Symbol
Md
Pa
Group Number
33
0
17
👆🏻
Period Number
77
2
7
👆🏻
Block
f block
f block
Element Family
Actinide
Actinide
CAS Number
74401117440133
7429905
54386242
👆🏻
Space Group Name
-
I4/mmm
Space Group Number
194.00139.00
11
276
👆🏻
Interesting Facts
- Mendelevium metal is synthetically produced metal.
- Mendelevium metal has been produced in only trace amount.
- Protactinium metal has 29 isotopes.
- Isotopes of Protactinium-231 used in nuclear weapon.
Sources
Bombarding Einsteinium with Helium Ions
Found in Uranium Ores, Mining, Ores of metals
History
Who Discovered
Lawrence Berkeley National Laboratory
William Crookes
Discovery
In 1955
In 1900
Abundance
Abundance In Universe
0.00 %0.00 %
0
0.11
👆🏻
Abundance In Sun
-0.00 %
0
0.1
👆🏻
Abundance In Meteorites
0.00 %-
0
22
👆🏻
Abundance In Earth's Crust
-0.00 %
1E-37
8.1
👆🏻
Abundance In Oceans
-0.00 %
0
1.1
👆🏻
Abundance In Humans
0.00 %0.00 %
0
1.4
👆🏻
Uses & Benefits
- Currently known uses of Mendelevium metal are limited to research purpose only.
- Currently known uses of Protactinium metal are limited to research purpose only.
Industrial Uses
-
-
Medical Uses
-
-
Other Uses
-
-
Biological Properties
Toxicity
-
Highly Toxic
Present in Human Body
✔
✘
✔
✘
In Blood
0.00 Blood/mg dm-30.00 Blood/mg dm-3
0
1970
👆🏻
In Bone
0.00 p.p.m.0.00 p.p.m.
0
170000
👆🏻
Melting Point
827.00 °C1,568.00 °C
-38.83
3410
👆🏻
Boiling Point
0.00 °C4,027.00 °C
0
5660
👆🏻
Appearance
Physical State
Solid
Solid
Color
-
Silver
Luster
Metallic
Metallic
Hardness
Mohs Hardness
-5.00
0.2
8.5
👆🏻
Brinell Hardness
350.00 MPa125.00 MPa
0.14
3490
👆🏻
Vickers Hardness
0.00 MPa220.00 MPa
0
3920
👆🏻
Speed of Sound
2,680.00 m/s12,400.00 m/s
818
16200
👆🏻
Optical Properties
Refractive Index
1.301.60
0.155
3.41
👆🏻
Reflectivity
66.00 %60.00 %
5
97
👆🏻
Allotropes
✔
✘
✔
✘
α Allotropes
-
-
β Allotropes
-
-
γ Allotropes
-
-
Chemical Formula
Md
Pa
Isotopes
Known Isotopes
1627
0
38
👆🏻
Electronegativity
Pauling Electronegativity
1.301.50
0
2.6
👆🏻
Sanderson Electronegativity
1.301.50
0.22
2.56
👆🏻
Allred Rochow Electronegativity
1.201.14
0.86
1.9
👆🏻
Mulliken-Jaffe Electronegativity
1.301.50
0.62
2.48
👆🏻
Allen Electronegativity
1.301.50
0.659
2.7
👆🏻
Electropositivity
Pauling Electropositivity
2.702.50
1.46
3.3
👆🏻
Ionization Energies
1st Energy Level
635.00 kJ/mol568.00 kJ/mol
375.7
26130
👆🏻
2nd Energy Level
1,235.00 kJ/mol1,128.00 kJ/mol
392.8
28750
👆🏻
3rd Energy Level
2,470.00 kJ/mol1,814.00 kJ/mol
392.8
34230
👆🏻
4th Energy Level
3,840.00 kJ/mol2,991.00 kJ/mol
375.7
37066
👆🏻
5th Energy Level
6,350.00 kJ/mol5,120.00 kJ/mol
392
97510
👆🏻
6th Energy Level
6,350.00 kJ/mol5,680.00 kJ/mol
1007
105800
👆🏻
7th Energy level
6,350.00 kJ/mol5,680.00 kJ/mol
1007
114300
👆🏻
8th Energy Level
6,350.00 kJ/mol5,680.00 kJ/mol
730
125300
👆🏻
9th Energy Level
6,350.00 kJ/mol5,120.00 kJ/mol
1007
134700
👆🏻
10th Energy Level
6,350.00 kJ/mol5,120.00 kJ/mol
392
144300
👆🏻
11th Energy Level
6,400.00 kJ/mol5,680.00 kJ/mol
392
169988
👆🏻
12th Energy Level
60,100.00 kJ/mol5,680.00 kJ/mol
0
189368
👆🏻
13th Energy Level
6,350.00 kJ/mol5,680.00 kJ/mol
1007
76015
👆🏻
14th Energy Level
1,150.00 kJ/mol5,680.00 kJ/mol
380
86450
👆🏻
15th Energy Level
63,500.00 kJ/mol56,800.00 kJ/mol
33000
100700
👆🏻
16th Energy Level
635.00 kJ/mol56,800.00 kJ/mol
375.7
109480
👆🏻
17th Energy Level
1,107.00 kJ/mol568.50 kJ/mol
375.7
122200
👆🏻
18th Energy Level
6,350.00 kJ/mol5,680.00 kJ/mol
0
134810
👆🏻
19th Energy Level
635.00 kJ/mol568.30 kJ/mol
375.7
148700
👆🏻
20th Energy Level
635.00 kJ/mol568.00 kJ/mol
0
171200
👆🏻
21st Energy Level
6,350.00 kJ/mol568.00 kJ/mol
375.7
179100
👆🏻
22nd Energy Level
635.00 kJ/mol568.00 kJ/mol
330
184900
👆🏻
23rd Energy Level
6,350.00 kJ/mol568.00 kJ/mol
357.6
198800
👆🏻
24th Energy Level
635.00 kJ/mol568.00 kJ/mol
297.3
195200
👆🏻
25th Energy Level
635.00 kJ/mol568.00 kJ/mol
0
121900
👆🏻
26th Energy Level
635.00 kJ/mol568.00 kJ/mol
357.6
127700
👆🏻
27th Energy Level
635.00 kJ/mol568.00 kJ/mol
0
133800
👆🏻
28th Energy Level
635.00 kJ/mol568.00 kJ/mol
297.3
139800
👆🏻
29th Energy Level
635.00 kJ/mol568.00 kJ/mol
0
148100
👆🏻
30th Energy Level
635.00 kJ/mol568.00 kJ/mol
0
154500
👆🏻
Electrochemical Equivalent
3.21 g/amp-hr1.72 g/amp-hr
0.16812
8.3209
👆🏻
Electron Work Function
3.89 eV5.89 eV
2.14
6
👆🏻
Other Chemical Properties
Ionization, Radioactive Isotopes, Radioactivity
Ionization, Radioactive Isotopes, Radioactivity
Atomic Number
10191
3
117
👆🏻
Electron Configuration
[Rn] 5f13 7s2
[Rn] 5f2 6d1 7s2
Crystal Structure
Not Known
Tetragonal (TETR)
Crystal Lattice
Atom
Number of Protons
10191
3
117
👆🏻
Number of Neutrons
157122
4
285
👆🏻
Number of Electrons
10191
3
117
👆🏻
Radius of an Atom
Atomic Radius
175.00 pm163.00 pm
0
348
👆🏻
Covalent Radius
175.00 pm200.00 pm
0
260
👆🏻
Van der Waals Radius
246.00 pm243.00 pm
0
348
👆🏻
Atomic Weight
258.00 amu231.04 amu
6.94
294
👆🏻
Atomic Volume
19.90 cm3/mol15.00 cm3/mol
1.39
71.07
👆🏻
Adjacent Atomic Numbers
Previous Element
Next Element
Valence Electron Potential
63.70 (-eV)92.00 (-eV)
0
392.42
👆🏻
Lattice Constant
-392.50 pm
0
891.25
👆🏻
Lattice Angles
-
π/2, π/2, π/2
Lattice C/A Ratio
1.581.58
0.423
1.9
👆🏻
Density
Density At Room Temperature
10.30 g/cm315.37 g/cm3
0.534
40.7
👆🏻
Density When Liquid (at m.p.)
10.30 g/cm315.37 g/cm3
0.512
41
👆🏻
Tensile Strength
80.00 MPa80.00 MPa
0.1
11000
👆🏻
Viscosity
0.000.00
1.5E-05
0.0035
👆🏻
Vapor Pressure
Vapor Pressure at 1000 K
0.00 (Pa)0.00 (Pa)
0
121
👆🏻
Vapor Pressure at 2000 K
0.00 (Pa)0.00 (Pa)
0
774
👆🏻
Elasticity properties
Shear Modulus
32.00 GPa16.00 GPa
1.3
222
👆🏻
Bulk Modulus
0.00 GPa47.00 GPa
0
462
👆🏻
Young's Modulus
12.00 GPa47.00 GPa
0
528
👆🏻
Poisson Ratio
0.300.23
0.032
0.47
👆🏻
Other Mechanical Properties
-
-
Magnetic Characteristics
Specific Gravity
13.5015.37
0.53
4500
👆🏻
Magnetic Ordering
-
Paramagnetic
Permeability
0.00 H/m0.00 H/m
1.25643E-06
0.0063
👆🏻
Susceptibility
0.000.00
-0.000166
200000
👆🏻
Electrical Properties
Electrical Property
-
Conductor
Resistivity
0.63 nΩ·m177.00 nΩ·m
0.1
961
👆🏻
Electrical Conductivity
0.00 106/cm Ω0.05 106/cm Ω
0
0.63
👆🏻
Electron Affinity
50.00 kJ/mol53.03 kJ/mol
0
222.8
👆🏻
Specific Heat
0.10 J/(kg K)0.12 J/(kg K)
0.1
3.6
👆🏻
Molar Heat Capacity
27.00 J/mol·K27.20 J/mol·K
13.1
62.7
👆🏻
Thermal Conductivity
0.00 W/m·K47.00 W/m·K
0
429
👆🏻
Critical Temperature
1,100.00 K1,841.00 K
26.3
3695
👆🏻
Thermal Expansion
11.60 µm/(m·K)9.90 µm/(m·K)
4.5
97
👆🏻
Enthalpy
Enthalpy of Vaporization
380.50 kJ/mol481.00 kJ/mol
7.32
799.1
👆🏻
Enthalpy of Fusion
-12.34 kJ/mol
2.1
35.23
👆🏻
Enthalpy of Atomization
410.80 kJ/mol481.90 kJ/mol
61.5
837
👆🏻
Standard Molar Entropy
37.40 J/mol.K198.10 J/mol.K
9.5
198.1
👆🏻