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Scandium vs Promethium


Promethium vs Scandium


Periodic Table

Symbol
Sc  
Pm  

Group Number
3  
15
3  
15

Period Number
4  
6  

Block
d block  
f block  

Element Family
Transition Metal  
Lanthanide  

CAS Number
7440202  
99+
7440122  
99+

Space Group Name
P63/mmc  
-  

Space Group Number
194.00  
7
194.00  
7

Facts

Interesting Facts
  • Scandium is known as one of the rare earth elements.
  • Scandium metal found in rare minerals called Wolframite .
  
  • Promethium metal found in Pitchblende.
  • Promethium metal is highly radioactive metal.
  

Sources
Found in Minerals, Mining, Ores of metals, Ores of Minerals  
Found in Minerals, Mining  

History
  
  

Who Discovered
Lars Fredrik Nilson  
Chien Shiung Wu, Emilio Segrè, Hans Bethe  

Discovery
In 1879  
In 1942  

Abundance
  
  

Abundance In Universe
0.00 %  
16
0.00 %  
40

Abundance In Sun
0.00 %  
16
-  

Abundance In Meteorites
0.00 %  
18
-  

Abundance In Earth's Crust
0.00 %  
23
0.00 %  
99+

Abundance In Oceans
0.00 %  
32
-  

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.
  
  • It is used for research purpose. Very small amount of this metal is used in atomic batteries.
  • Its radioactive decay is used for a phosphor to give off light. The light emitted is converted into electricity.
  

Industrial Uses
Electrical Industry, Electronic Industry  
-  

Medical Uses
-  
-  

Other Uses
Alloys  
-  

Biological Properties
  
  

Toxicity
Non Toxic  
Non 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
1,042.00 °C  
99+

Boiling Point
2,832.00 °C  
36
3,000.00 °C  
32

Appearance
  
  

Physical State
Solid  
Solid  

Color
Silvery White  
-  

Luster
Lustrous  
Metallic  

Hardness
  
  

Mohs Hardness
5.50  
7
-  

Brinell Hardness
750.00 MPa  
13
400.00 MPa  
34

Vickers Hardness
1,200.00 MPa  
13
600.00 MPa  
28

Speed of Sound
6,100.00 m/s  
5
2,260.00 m/s  
99+

Optical Properties
  
  

Refractive Index
1.80  
21
1.70  
27

Reflectivity
93.00 %  
3
63.00 %  
20

Allotropes
No  
No  

α Allotropes
-  
-  

β Allotropes
-  
-  

γ Allotropes
-  
-  

Chemical

Chemical Formula
Sc  
Pm  

Isotopes
  
  

Known Isotopes
13  
26
27  
12

Electronegativity
  
  

Pauling Electronegativity
1.36  
30
1.13  
99+

Sanderson Electronegativity
1.02  
40
1.13  
36

Allred Rochow Electronegativity
1.20  
28
1.07  
33

Mulliken-Jaffe Electronegativity
1.36  
31
1.13  
99+

Allen Electronegativity
1.19  
99+
1.13  
99+

Electropositivity
  
  

Pauling Electropositivity
2.64  
25
2.20  
39

Ionization Energies
  
  

1st Energy Level
633.10 kJ/mol  
99+
540.00 kJ/mol  
99+

2nd Energy Level
1,235.00 kJ/mol  
99+
1,050.00 kJ/mol  
99+

3rd Energy Level
2,388.60 kJ/mol  
99+
2,150.00 kJ/mol  
99+

4th Energy Level
7,090.60 kJ/mol  
13
3,970.00 kJ/mol  
99+

5th Energy Level
8,843.00 kJ/mol  
7
5,400.00 kJ/mol  
99+

6th Energy Level
10,679.00 kJ/mol  
13
5,400.00 kJ/mol  
99+

7th Energy level
13,310.00 kJ/mol  
8
5,400.00 kJ/mol  
99+

8th Energy Level
15,250.00 kJ/mol  
11
5,400.00 kJ/mol  
99+

9th Energy Level
17,370.00 kJ/mol  
14
5,400.00 kJ/mol  
99+

10th Energy Level
21,726.00 kJ/mol  
13
5,400.00 kJ/mol  
99+

11th Energy Level
24,102.00 kJ/mol  
16
5,400.00 kJ/mol  
99+

12th Energy Level
66,320.00 kJ/mol  
7
5,400.00 kJ/mol  
99+

13th Energy Level
73,010.00 kJ/mol  
2
5,400.00 kJ/mol  
99+

14th Energy Level
80,160.00 kJ/mol  
3
5,400.00 kJ/mol  
99+

15th Energy Level
89,490.00 kJ/mol  
6
54,000.00 kJ/mol  
99+

16th Energy Level
97,400.00 kJ/mol  
5
54,000.00 kJ/mol  
99+

17th Energy Level
105,600.00 kJ/mol  
6
540.50 kJ/mol  
99+

18th Energy Level
117,000.00 kJ/mol  
7
5,400.00 kJ/mol  
99+

19th Energy Level
124,270.00 kJ/mol  
8
540.00 kJ/mol  
99+

20th Energy Level
633.00 kJ/mol  
99+
540.00 kJ/mol  
99+

21st Energy Level
633.10 kJ/mol  
99+
540.00 kJ/mol  
99+

22nd Energy Level
633.00 kJ/mol  
35
540.00 kJ/mol  
99+

23rd Energy Level
633.10 kJ/mol  
99+
540.00 kJ/mol  
99+

24th Energy Level
633.10 kJ/mol  
37
540.00 kJ/mol  
99+

25th Energy Level
633.00 kJ/mol  
39
540.00 kJ/mol  
99+

26th Energy Level
633.10 kJ/mol  
38
540.00 kJ/mol  
99+

27th Energy Level
633.10 kJ/mol  
40
540.00 kJ/mol  
99+

28th Energy Level
633.10 kJ/mol  
99+
540.00 kJ/mol  
99+

29th Energy Level
633.10 kJ/mol  
99+
540.00 kJ/mol  
99+

30th Energy Level
633.00 kJ/mol  
99+
540.00 kJ/mol  
99+

Electrochemical Equivalent
0.56 g/amp-hr  
99+
1.80 g/amp-hr  
40

Electron Work Function
3.50 eV  
99+
5.30 eV  
5

Other Chemical Properties
Corrosion, Flammable, Ionization, Radioactive Isotopes, Solubility  
Ionization, Radioactive Isotopes, Solubility  

Atomic

Atomic Number
21  
99+
61  
99+

Electron Configuration
[Ar] 3d1 4s2  
[Xe] 4f5 6s2  

Crystal Structure
Hexagonal Close Packed (HCP)  
Double Hexagonal Close Packed (DHCP)  

Crystal Lattice
HCP-Crystal-Structure-of-Scandium.jpg#100  
DHCP-Crystal-Structure-of-Promethium.jpg#100  

Atom
  
  

Number of Protons
21  
99+
61  
99+

Number of Neutrons
24  
99+
84  
99+

Number of Electrons
21  
99+
61  
99+

Radius of an Atom
  
  

Atomic Radius
162.00 pm  
28
183.00 pm  
12

Covalent Radius
170.00 pm  
27
199.00 pm  
12

Van der Waals Radius
211.00 pm  
32
236.00 pm  
20

Atomic Weight
44.96 amu  
99+
145.00 amu  
99+

Atomic Volume
15.00 cm3/mol  
99+
22.39 cm3/mol  
21

Adjacent Atomic Numbers
  
  

Previous Element
Calcium
  
Neodymium
  

Next Element
Titanium
  
Samarium
  

Valence Electron Potential
58.00 (-eV)  
25
44.10 (-eV)  
40

Lattice Constant
330.90 pm  
99+
-  

Lattice Angles
π/2, π/2, 2 π/3  
-  

Lattice C/A Ratio
1.59  
24
1.63  
14

Mechanical

Density
  
  

Density At Room Temperature
2.99 g/cm3  
99+
7.26 g/cm3  
99+

Density When Liquid (at m.p.)
2.80 g/cm3  
99+
7.26 g/cm3  
99+

Tensile Strength
150.00 MPa  
25
75.00 MPa  
30

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)  
31

Elasticity properties
  
  

Shear Modulus
29.10 GPa  
28
18.00 GPa  
99+

Bulk Modulus
56.60 GPa  
22
33.00 GPa  
99+

Young's Modulus
74.40 GPa  
28
46.00 GPa  
99+

Poisson Ratio
0.28  
18
0.28  
17

Other Mechanical Properties
-  
-  

Magnetic

Magnetic Characteristics
  
  

Specific Gravity
2.99  
99+
7.26  
99+

Magnetic Ordering
Paramagnetic  
Paramagnetic  

Permeability
0.00 H/m  
8
0.00 H/m  
11

Susceptibility
0.00  
24
0.00  
25

Electrical Properties
  
  

Electrical Property
Conductor  
Conductor  

Resistivity
562.00 nΩ·m  
10
0.75 nΩ·m  
99+

Electrical Conductivity
0.02 106/cm Ω  
99+
0.00 106/cm Ω  
99+

Electron Affinity
18.10 kJ/mol  
39
50.00 kJ/mol  
26

Thermal

Specific Heat
0.60 J/(kg K)  
8
0.18 J/(kg K)  
34

Molar Heat Capacity
25.52 J/mol·K  
99+
27.60 J/mol·K  
20

Thermal Conductivity
15.80 W/m·K  
99+
17.90 W/m·K  
99+

Critical Temperature
1,814.00 K  
28
1,315.00 K  
99+

Thermal Expansion
10.20 µm/(m·K)  
99+
9.00 µm/(m·K)  
99+

Enthalpy
  
  

Enthalpy of Vaporization
314.20 kJ/mol  
99+
289.00 kJ/mol  
99+

Enthalpy of Fusion
14.10 kJ/mol  
29
7.50 kJ/mol  
99+

Enthalpy of Atomization
343.00 kJ/mol  
38
310.00 kJ/mol  
99+

Standard Molar Entropy
34.60 J/mol.K  
99+
57.00 J/mol.K  
30

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