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Scandium vs Protactinium

Scandium
Protactinium
Protactinium vs Scandium


Periodic Table
Symbol
Sc  
Pa  
Group Number
3  
15
3  
15
Period Number
4  
7  
Block
d block  
f block  
Element Family
Transition Metal  
Actinide  
CAS Number
7440202  
99+
7440133  
99+
Space Group Name
P63/mmc  
I4/mmm  
Space Group Number
194.00  
7
139.00  
11
Facts
Interesting Facts
  • Scandium is known as one of the rare earth elements.
  • Scandium metal found in rare minerals called Wolframite .
  
  • Protactinium metal has 29 isotopes.
  • Isotopes of Protactinium-231 used in nuclear weapon.
  
Sources
Found in Minerals, Mining, Ores of metals, Ores of Minerals  
Found in Uranium Ores, Mining, Ores of metals  
History
  
  
Who Discovered
Lars Fredrik Nilson  
William Crookes  
Discovery
In 1879  
In 1900  
Abundance
  
  
Abundance In Universe
0.00 %  
16
0.00 %  
17
Abundance In Sun
0.00 %  
16
0.00 %  
26
Abundance In Meteorites
0.00 %  
18
-  
Abundance In Earth's Crust
0.00 %  
23
0.00 %  
99+
Abundance In Oceans
0.00 %  
32
0.00 %  
99+
Abundance In Humans
0.00 %  
24
0.00 %  
24
Uses
Uses & Benefits
  • 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.
  
  • Currently known uses of Protactinium metal are limited to research purpose only.
  
Industrial Uses
Electrical Industry, Electronic Industry  
-  
Medical Uses
-  
-  
Other Uses
Alloys  
-  
Biological Properties
  
  
Toxicity
Non Toxic  
Highly Toxic  
Present in Human Body
Yes  
No  
In Blood
0.01 Blood/mg dm-3  
22
0.00 Blood/mg dm-3  
40
In Bone
0.00 p.p.m.  
39
0.00 p.p.m.  
99+
Physical
Melting Point
1,539.00 °C  
24
1,568.00 °C  
21
Boiling Point
2,832.00 °C  
36
4,027.00 °C  
12
Appearance
  
  
Physical State
Solid  
Solid  
Color
Silvery White  
Silver  
Luster
Lustrous  
Metallic  
Hardness
  
  
Mohs Hardness
5.50  
7
5.00  
8
Brinell Hardness
750.00 MPa  
13
125.00 MPa  
99+
Vickers Hardness
1,200.00 MPa  
13
220.00 MPa  
99+
Speed of Sound
6,100.00 m/s  
5
12,400.00 m/s  
3
Optical Properties
  
  
Refractive Index
1.80  
21
1.60  
33
Reflectivity
93.00 %  
3
60.00 %  
23
Allotropes
No  
No  
α Allotropes
-  
-  
β Allotropes
-  
-  
γ Allotropes
-  
-  
Chemical
Chemical Formula
Sc  
Pa  
Isotopes
  
  
Known Isotopes
13  
26
27  
12
Electronegativity
  
  
Pauling Electronegativity
1.36  
30
1.50  
28
Sanderson Electronegativity
1.02  
40
1.50  
18
Allred Rochow Electronegativity
1.20  
28
1.14  
29
Mulliken-Jaffe Electronegativity
1.36  
31
1.50  
26
Allen Electronegativity
1.19  
99+
1.50  
32
Electropositivity
  
  
Pauling Electropositivity
2.64  
25
2.50  
27
Ionization Energies
  
  
1st Energy Level
633.10 kJ/mol  
99+
568.00 kJ/mol  
99+
2nd Energy Level
1,235.00 kJ/mol  
99+
1,128.00 kJ/mol  
99+
3rd Energy Level
2,388.60 kJ/mol  
99+
1,814.00 kJ/mol  
99+
4th Energy Level
7,090.60 kJ/mol  
13
2,991.00 kJ/mol  
99+
5th Energy Level
8,843.00 kJ/mol  
7
5,120.00 kJ/mol  
99+
6th Energy Level
10,679.00 kJ/mol  
13
5,680.00 kJ/mol  
99+
7th Energy level
13,310.00 kJ/mol  
8
5,680.00 kJ/mol  
99+
8th Energy Level
15,250.00 kJ/mol  
11
5,680.00 kJ/mol  
99+
9th Energy Level
17,370.00 kJ/mol  
14
5,120.00 kJ/mol  
99+
10th Energy Level
21,726.00 kJ/mol  
13
5,120.00 kJ/mol  
99+
11th Energy Level
24,102.00 kJ/mol  
16
5,680.00 kJ/mol  
99+
12th Energy Level
66,320.00 kJ/mol  
7
5,680.00 kJ/mol  
99+
13th Energy Level
73,010.00 kJ/mol  
2
5,680.00 kJ/mol  
99+
14th Energy Level
80,160.00 kJ/mol  
3
5,680.00 kJ/mol  
99+
15th Energy Level
89,490.00 kJ/mol  
6
56,800.00 kJ/mol  
99+
16th Energy Level
97,400.00 kJ/mol  
5
56,800.00 kJ/mol  
99+
17th Energy Level
105,600.00 kJ/mol  
6
568.50 kJ/mol  
99+
18th Energy Level
117,000.00 kJ/mol  
7
5,680.00 kJ/mol  
99+
19th Energy Level
124,270.00 kJ/mol  
8
568.30 kJ/mol  
99+
20th Energy Level
633.00 kJ/mol  
99+
568.00 kJ/mol  
99+
21st Energy Level
633.10 kJ/mol  
99+
568.00 kJ/mol  
99+
22nd Energy Level
633.00 kJ/mol  
35
568.00 kJ/mol  
99+
23rd Energy Level
633.10 kJ/mol  
99+
568.00 kJ/mol  
99+
24th Energy Level
633.10 kJ/mol  
37
568.00 kJ/mol  
99+
25th Energy Level
633.00 kJ/mol  
39
568.00 kJ/mol  
99+
26th Energy Level
633.10 kJ/mol  
38
568.00 kJ/mol  
99+
27th Energy Level
633.10 kJ/mol  
40
568.00 kJ/mol  
99+
28th Energy Level
633.10 kJ/mol  
99+
568.00 kJ/mol  
99+
29th Energy Level
633.10 kJ/mol  
99+
568.00 kJ/mol  
99+
30th Energy Level
633.00 kJ/mol  
99+
568.00 kJ/mol  
99+
Electrochemical Equivalent
0.56 g/amp-hr  
99+
1.72 g/amp-hr  
99+
Electron Work Function
3.50 eV  
99+
5.89 eV  
3
Other Chemical Properties
Corrosion, Flammable, Ionization, Radioactive Isotopes, Solubility  
Ionization, Radioactive Isotopes, Radioactivity  
Atomic
Atomic Number
21  
99+
91  
27
Electron Configuration
[Ar] 3d1 4s2  
[Rn] 5f2 6d1 7s2  
Crystal Structure
Hexagonal Close Packed (HCP)  
Tetragonal (TETR)  
Crystal Lattice
HCP-Crystal-Structure-of-Scandium.jpg#100  
TETR-Crystal-Structure-of-Protactinium.jpg#100  
Atom
  
  
Number of Protons
21  
99+
91  
27
Number of Neutrons
24  
99+
122  
22
Number of Electrons
21  
99+
91  
27
Radius of an Atom
  
  
Atomic Radius
162.00 pm  
28
163.00 pm  
27
Covalent Radius
170.00 pm  
27
200.00 pm  
11
Van der Waals Radius
211.00 pm  
32
243.00 pm  
15
Atomic Weight
44.96 amu  
99+
231.04 amu  
24
Atomic Volume
15.00 cm3/mol  
99+
15.00 cm3/mol  
99+
Adjacent Atomic Numbers
  
  
Previous Element
Calcium
  
Thorium
  
Next Element
Titanium
  
Uranium
  
Valence Electron Potential
58.00 (-eV)  
25
92.00 (-eV)  
11
Lattice Constant
330.90 pm  
99+
392.50 pm  
26
Lattice Angles
π/2, π/2, 2 π/3  
π/2, π/2, π/2  
Lattice C/A Ratio
1.59  
24
1.58  
36
Mechanical
Density
  
  
Density At Room Temperature
2.99 g/cm3  
99+
15.37 g/cm3  
20
Density When Liquid (at m.p.)
2.80 g/cm3  
99+
15.37 g/cm3  
21
Tensile Strength
150.00 MPa  
25
80.00 MPa  
29
Viscosity
0.00  
25
0.00  
25
Vapor Pressure
  
  
Vapor Pressure at 1000 K
0.00 (Pa)  
24
0.00 (Pa)  
37
Vapor Pressure at 2000 K
91.30 (Pa)  
3
0.00 (Pa)  
32
Elasticity properties
  
  
Shear Modulus
29.10 GPa  
28
16.00 GPa  
99+
Bulk Modulus
56.60 GPa  
22
47.00 GPa  
26
Young's Modulus
74.40 GPa  
28
47.00 GPa  
99+
Poisson Ratio
0.28  
18
0.23  
30
Other Mechanical Properties
-  
-  
Magnetic
Magnetic Characteristics
  
  
Specific Gravity
2.99  
99+
15.37  
23
Magnetic Ordering
Paramagnetic  
Paramagnetic  
Permeability
0.00 H/m  
8
0.00 H/m  
10
Susceptibility
0.00  
24
0.00  
21
Electrical Properties
  
  
Electrical Property
Conductor  
Conductor  
Resistivity
562.00 nΩ·m  
10
177.00 nΩ·m  
21
Electrical Conductivity
0.02 106/cm Ω  
99+
0.05 106/cm Ω  
39
Electron Affinity
18.10 kJ/mol  
39
53.03 kJ/mol  
22
Thermal
Specific Heat
0.60 J/(kg K)  
8
0.12 J/(kg K)  
99+
Molar Heat Capacity
25.52 J/mol·K  
99+
27.20 J/mol·K  
24
Thermal Conductivity
15.80 W/m·K  
99+
47.00 W/m·K  
32
Critical Temperature
1,814.00 K  
28
1,841.00 K  
25
Thermal Expansion
10.20 µm/(m·K)  
99+
9.90 µm/(m·K)  
99+
Enthalpy
  
  
Enthalpy of Vaporization
314.20 kJ/mol  
99+
481.00 kJ/mol  
17
Enthalpy of Fusion
14.10 kJ/mol  
29
12.34 kJ/mol  
34
Enthalpy of Atomization
343.00 kJ/mol  
38
481.90 kJ/mol  
19
Standard Molar Entropy
34.60 J/mol.K  
99+
198.10 J/mol.K  
1
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