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Protactinium vs Scandium

Protactinium
Scandium
Scandium vs Protactinium


Periodic Table
Symbol
Pa  
Sc  
Group Number
3  
15
3  
15
Period Number
7  
4  
Block
f block  
d block  
Element Family
Actinide  
Transition Metal  
CAS Number
7440133  
99+
7440202  
99+
Space Group Name
I4/mmm  
P63/mmc  
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.
  
  • Scandium is known as one of the rare earth elements.
  • Scandium metal found in rare minerals called Wolframite .
  
Sources
Found in Uranium Ores, Mining, Ores of metals  
Found in Minerals, Mining, Ores of metals, Ores of Minerals  
History
  
  
Who Discovered
William Crookes  
Lars Fredrik Nilson  
Discovery
In 1900  
In 1879  
Abundance
  
  
Abundance In Universe
0.00 %  
17
0.00 %  
16
Abundance In Sun
0.00 %  
26
0.00 %  
16
Abundance In Meteorites
-  
0.00 %  
18
Abundance In Earth's Crust
0.00 %  
99+
0.00 %  
23
Abundance In Oceans
0.00 %  
99+
0.00 %  
32
Abundance In Humans
0.00 %  
24
0.00 %  
24
Uses
Uses & Benefits
  • Currently known uses of Protactinium metal are limited to research purpose only.
  
  • Uses of Scandium are limited to research purpose only. However, it has very low density and higher melting point.
  • Its compounds like scandium iodide is used in mercury vapor lamps to produce very bright white light.
  
Industrial Uses
-  
Electrical Industry, Electronic Industry  
Medical Uses
-  
-  
Other Uses
-  
Alloys  
Biological Properties
  
  
Toxicity
Highly Toxic  
Non Toxic  
Present in Human Body
No  
Yes  
In Blood
0.00 Blood/mg dm-3  
40
0.01 Blood/mg dm-3  
22
In Bone
0.00 p.p.m.  
99+
0.00 p.p.m.  
39
Physical
Melting Point
1,568.00 °C  
21
1,539.00 °C  
24
Boiling Point
4,027.00 °C  
12
2,832.00 °C  
36
Appearance
  
  
Physical State
Solid  
Solid  
Color
Silver  
Silvery White  
Luster
Metallic  
Lustrous  
Hardness
  
  
Mohs Hardness
5.00  
8
5.50  
7
Brinell Hardness
125.00 MPa  
99+
750.00 MPa  
13
Vickers Hardness
220.00 MPa  
99+
1,200.00 MPa  
13
Speed of Sound
12,400.00 m/s  
3
6,100.00 m/s  
5
Optical Properties
  
  
Refractive Index
1.60  
33
1.80  
21
Reflectivity
60.00 %  
23
93.00 %  
3
Allotropes
No  
No  
α Allotropes
-  
-  
β Allotropes
-  
-  
γ Allotropes
-  
-  
Chemical
Chemical Formula
Pa  
Sc  
Isotopes
  
  
Known Isotopes
27  
12
13  
26
Electronegativity
  
  
Pauling Electronegativity
1.50  
28
1.36  
30
Sanderson Electronegativity
1.50  
18
1.02  
40
Allred Rochow Electronegativity
1.14  
29
1.20  
28
Mulliken-Jaffe Electronegativity
1.50  
26
1.36  
31
Allen Electronegativity
1.50  
32
1.19  
99+
Electropositivity
  
  
Pauling Electropositivity
2.50  
27
2.64  
25
Ionization Energies
  
  
1st Energy Level
568.00 kJ/mol  
99+
633.10 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+
2,388.60 kJ/mol  
99+
4th Energy Level
2,991.00 kJ/mol  
99+
7,090.60 kJ/mol  
13
5th Energy Level
5,120.00 kJ/mol  
99+
8,843.00 kJ/mol  
7
6th Energy Level
5,680.00 kJ/mol  
99+
10,679.00 kJ/mol  
13
7th Energy level
5,680.00 kJ/mol  
99+
13,310.00 kJ/mol  
8
8th Energy Level
5,680.00 kJ/mol  
99+
15,250.00 kJ/mol  
11
9th Energy Level
5,120.00 kJ/mol  
99+
17,370.00 kJ/mol  
14
10th Energy Level
5,120.00 kJ/mol  
99+
21,726.00 kJ/mol  
13
11th Energy Level
5,680.00 kJ/mol  
99+
24,102.00 kJ/mol  
16
12th Energy Level
5,680.00 kJ/mol  
99+
66,320.00 kJ/mol  
7
13th Energy Level
5,680.00 kJ/mol  
99+
73,010.00 kJ/mol  
2
14th Energy Level
5,680.00 kJ/mol  
99+
80,160.00 kJ/mol  
3
15th Energy Level
56,800.00 kJ/mol  
99+
89,490.00 kJ/mol  
6
16th Energy Level
56,800.00 kJ/mol  
99+
97,400.00 kJ/mol  
5
17th Energy Level
568.50 kJ/mol  
99+
105,600.00 kJ/mol  
6
18th Energy Level
5,680.00 kJ/mol  
99+
117,000.00 kJ/mol  
7
19th Energy Level
568.30 kJ/mol  
99+
124,270.00 kJ/mol  
8
20th Energy Level
568.00 kJ/mol  
99+
633.00 kJ/mol  
99+
21st Energy Level
568.00 kJ/mol  
99+
633.10 kJ/mol  
99+
22nd Energy Level
568.00 kJ/mol  
99+
633.00 kJ/mol  
35
23rd Energy Level
568.00 kJ/mol  
99+
633.10 kJ/mol  
99+
24th Energy Level
568.00 kJ/mol  
99+
633.10 kJ/mol  
37
25th Energy Level
568.00 kJ/mol  
99+
633.00 kJ/mol  
39
26th Energy Level
568.00 kJ/mol  
99+
633.10 kJ/mol  
38
27th Energy Level
568.00 kJ/mol  
99+
633.10 kJ/mol  
40
28th Energy Level
568.00 kJ/mol  
99+
633.10 kJ/mol  
99+
29th Energy Level
568.00 kJ/mol  
99+
633.10 kJ/mol  
99+
30th Energy Level
568.00 kJ/mol  
99+
633.00 kJ/mol  
99+
Electrochemical Equivalent
1.72 g/amp-hr  
99+
0.56 g/amp-hr  
99+
Electron Work Function
5.89 eV  
3
3.50 eV  
99+
Other Chemical Properties
Ionization, Radioactive Isotopes, Radioactivity  
Corrosion, Flammable, Ionization, Radioactive Isotopes, Solubility  
Atomic
Atomic Number
91  
27
21  
99+
Electron Configuration
[Rn] 5f2 6d1 7s2  
[Ar] 3d1 4s2  
Crystal Structure
Tetragonal (TETR)  
Hexagonal Close Packed (HCP)  
Crystal Lattice
TETR-Crystal-Structure-of-Protactinium.jpg#100  
HCP-Crystal-Structure-of-Scandium.jpg#100  
Atom
  
  
Number of Protons
91  
27
21  
99+
Number of Neutrons
122  
22
24  
99+
Number of Electrons
91  
27
21  
99+
Radius of an Atom
  
  
Atomic Radius
163.00 pm  
27
162.00 pm  
28
Covalent Radius
200.00 pm  
11
170.00 pm  
27
Van der Waals Radius
243.00 pm  
15
211.00 pm  
32
Atomic Weight
231.04 amu  
24
44.96 amu  
99+
Atomic Volume
15.00 cm3/mol  
99+
15.00 cm3/mol  
99+
Adjacent Atomic Numbers
  
  
Previous Element
Thorium
  
Calcium
  
Next Element
Uranium
  
Titanium
  
Valence Electron Potential
92.00 (-eV)  
11
58.00 (-eV)  
25
Lattice Constant
392.50 pm  
26
330.90 pm  
99+
Lattice Angles
π/2, π/2, π/2  
π/2, π/2, 2 π/3  
Lattice C/A Ratio
1.58  
36
1.59  
24
Mechanical
Density
  
  
Density At Room Temperature
15.37 g/cm3  
20
2.99 g/cm3  
99+
Density When Liquid (at m.p.)
15.37 g/cm3  
21
2.80 g/cm3  
99+
Tensile Strength
80.00 MPa  
29
150.00 MPa  
25
Viscosity
0.00  
25
0.00  
25
Vapor Pressure
  
  
Vapor Pressure at 1000 K
0.00 (Pa)  
37
0.00 (Pa)  
24
Vapor Pressure at 2000 K
0.00 (Pa)  
32
91.30 (Pa)  
3
Elasticity properties
  
  
Shear Modulus
16.00 GPa  
99+
29.10 GPa  
28
Bulk Modulus
47.00 GPa  
26
56.60 GPa  
22
Young's Modulus
47.00 GPa  
99+
74.40 GPa  
28
Poisson Ratio
0.23  
30
0.28  
18
Other Mechanical Properties
-  
-  
Magnetic
Magnetic Characteristics
  
  
Specific Gravity
15.37  
23
2.99  
99+
Magnetic Ordering
Paramagnetic  
Paramagnetic  
Permeability
0.00 H/m  
10
0.00 H/m  
8
Susceptibility
0.00  
21
0.00  
24
Electrical Properties
  
  
Electrical Property
Conductor  
Conductor  
Resistivity
177.00 nΩ·m  
21
562.00 nΩ·m  
10
Electrical Conductivity
0.05 106/cm Ω  
39
0.02 106/cm Ω  
99+
Electron Affinity
53.03 kJ/mol  
22
18.10 kJ/mol  
39
Thermal
Specific Heat
0.12 J/(kg K)  
99+
0.60 J/(kg K)  
8
Molar Heat Capacity
27.20 J/mol·K  
24
25.52 J/mol·K  
99+
Thermal Conductivity
47.00 W/m·K  
32
15.80 W/m·K  
99+
Critical Temperature
1,841.00 K  
25
1,814.00 K  
28
Thermal Expansion
9.90 µm/(m·K)  
99+
10.20 µm/(m·K)  
99+
Enthalpy
  
  
Enthalpy of Vaporization
481.00 kJ/mol  
17
314.20 kJ/mol  
99+
Enthalpy of Fusion
12.34 kJ/mol  
34
14.10 kJ/mol  
29
Enthalpy of Atomization
481.90 kJ/mol  
19
343.00 kJ/mol  
38
Standard Molar Entropy
198.10 J/mol.K  
1
34.60 J/mol.K  
99+
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