Scandium vs Protactinium
Periodic Table
Symbol
Sc
Pa
Group Number
3
15
Not Available
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
5
139.00
8
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
3 * 10-6 %
15
Not Available
Abundance In Sun
~0.000004 %
16
~-9999 %
Abundance In Meteorites
0.00 %
18
Not Available
Abundance In Earth's Crust
0.00 %
23
0.00 %
99+
Abundance In Oceans
0.00 %
32
0.00 %
99+
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
NA
Medical Uses
NA
NA
Other Uses
Alloys
NA
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
37
In Bone
0.00 p.p.m.
34
0.00 p.p.m.
36
Physical Properties
Melting Point
1,539.00 °C
24
1,568.00 °C
21
Boiling Point
2,832.00 °C
35
4,027.00 °C
12
Appearance
Physical State
Solid
Solid
Color
Silvery White
Silver
Luster
Lustrous
Metallic
Hardness
Brinell Hardness
750.00 MPa
12
Not Available
Speed of Sound
Not Available
Not Available
Optical Properties
Allotropes
No
No
α Allotropes
Not Available
Not Available
β Allotropes
Not Available
Not Available
γ Allotropes
Not Available
Not Available
Chemical Properties
Chemical Formula
Sc
Pa
Isotopes
Known Isotopes
13
26
27
12
Electronegativity
Pauling Electronegativity
1.36
29
1.50
27
Sanderson Electronegativity
1.02
21
Not Available
Allred Rochow Electronegativity
1.20
27
1.14
28
Allen Electronegativity
1.19
36
Not Available
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
6
2,991.00 kJ/mol
99+
5th Energy Level
8,843.00 kJ/mol
6
Not Available
6th Energy Level
10,679.00 kJ/mol
7
Not Available
7th Energy level
13,310.00 kJ/mol
8
Not Available
8th Energy Level
15,250.00 kJ/mol
11
Not Available
9th Energy Level
17,370.00 kJ/mol
14
Not Available
10th Energy Level
21,726.00 kJ/mol
13
Not Available
11th Energy Level
24,102.00 kJ/mol
16
Not Available
12th Energy Level
66,320.00 kJ/mol
2
Not Available
13th Energy Level
73,010.00 kJ/mol
2
Not Available
14th Energy Level
80,160.00 kJ/mol
3
Not Available
15th Energy Level
89,490.00 kJ/mol
4
Not Available
16th Energy Level
97,400.00 kJ/mol
5
Not Available
17th Energy Level
105,600.00 kJ/mol
6
Not Available
18th Energy Level
117,000.00 kJ/mol
7
Not Available
19th Energy Level
124,270.00 kJ/mol
8
Not Available
Electrochemical Equivalent
0.56 g/amp-hr
99+
1.72 g/amp-hr
99+
Electron Work Function
3.50 eV
31
Not Available
Other Chemical Properties
Corrosion, Flammable, Ionization, Radioactive Isotopes, Solubility
Ionization, Radioactive Isotopes, Radioactivity
Atomic Properties
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
21
Number of Electrons
21
99+
91
27
Radius of an Atom
Atomic Radius
162.00 pm
26
163.00 pm
25
Covalent Radius
170.00 pm
25
200.00 pm
11
Van der Waals Radius
211.00 pm
25
243.00 pm
11
Atomic Weight
44.96 amu
99+
231.04 amu
24
Atomic Volume
15.00 cm3/mol
34
15.00 cm3/mol
34
Adjacent Atomic Numbers
Valence Electron Potential
58.00 (-eV)
24
92.00 (-eV)
11
Lattice Constant
330.90 pm
99+
392.50 pm
23
Lattice Angles
π/2, π/2, 2 π/3
π/2, π/2, π/2
Lattice C/A Ratio
1.59
7
Not Available
Mechanical Properties
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+
Not Available
Tensile Strength
Not Available
Not Available
Viscosity
Not Available
Not Available
Vapor Pressure
Vapor Pressure at 1000 K
0.00 (Pa)
22
Not Available
Vapor Pressure at 2000 K
91.30 (Pa)
3
Not Available
Elasticity properties
Shear Modulus
29.10 GPa
24
Not Available
Bulk Modulus
56.60 GPa
21
Not Available
Young's Modulus
74.40 GPa
26
Not Available
Poisson Ratio
0.28
18
Not Available
Other Mechanical Properties
NA
Unknown
Magnetic Properties
Magnetic Characteristics
Specific Gravity
2.99
99+
15.37
12
Magnetic Ordering
Paramagnetic
Paramagnetic
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
34
Electron Affinity
18.10 kJ/mol
33
Not Available
Thermal Properties
Specific Heat
0.60 J/(kg K)
8
0.12 J/(kg K)
40
Molar Heat Capacity
25.52 J/mol·K
37
Not Available
Thermal Conductivity
15.80 W/m·K
99+
47.00 W/m·K
32
Critical Temperature
Not Available
Not Available
Thermal Expansion
10.20 µm/(m·K)
39
9.90 µm/(m·K)
40
Enthalpy
Enthalpy of Vaporization
314.20 kJ/mol
28
Not Available
Enthalpy of Fusion
14.10 kJ/mol
25
12.34 kJ/mol
28
Enthalpy of Atomization
343.00 kJ/mol
28
Not Available
Standard Molar Entropy
34.60 J/mol.K
99+
198.10 J/mol.K
1
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