Americium Protactinium Comparison
Periodic Table
Symbol
Am
Pa
Group Number
Not Available
Not Available
Period Number
7
7
Block
f block
f block
Element Family
Actinide
Actinide
CAS Number
7440359
99+
7440133
99+
Space Group Name
P63/mmc
I4/mmm
Space Group Number
194.00
5
139.00
8
Facts
Interesting Facts
- Americium metal is produced by bombarding Plutonium with Neutrons.
- Americium metal was discovered as a by-product while testing an atomic bomb (Manhattan Project).
- Protactinium metal has 29 isotopes.
- Isotopes of Protactinium-231 used in nuclear weapon.
Sources
Obtained By Bombarding Plutonium with Neutrons
Found in Uranium Ores, Mining, Ores of metals
History
Who Discovered
Glenn T. Seaborg, Ralph A. James, Leon O. Morgan, Albert Ghiorso
William Crookes
Discovery
In 1944
In 1900
Abundance
Abundance In Earth's Crust
Not Available
0.00 %
99+
Abundance In Oceans
Not Available
0.00 %
99+
Uses
Uses & Benefits
- Americium metal is used in smoke detection alarms.
- In the future, this metal has a potential to be used in batteries of spacecrafts.
- Currently known uses of Protactinium metal are limited to research purpose only.
Industrial Uses
NA
NA
Medical Uses
NA
NA
Other Uses
Alloys, Nuclear Research, Research Purposes
NA
Biological Properties
Toxicity
Toxic
Highly Toxic
Present in Human Body
No
No
In Blood
0.00 Blood/mg dm-3
37
0.00 Blood/mg dm-3
37
In Bone
0.00 p.p.m.
36
0.00 p.p.m.
36
Physical Properties
Melting Point
994.00 °C
99+
1,568.00 °C
21
Boiling Point
2,607.00 °C
99+
4,027.00 °C
12
Appearance
Physical State
Solid
Solid
Color
Silvery White
Silver
Luster
NA
Metallic
Hardness
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
Am
Pa
Isotopes
Known Isotopes
16
23
27
12
Electronegativity
Pauling Electronegativity
1.30
32
1.50
27
Allred Rochow Electronegativity
1.20
27
1.14
28
Electropositivity
Pauling Electropositivity
2.70
22
2.50
27
Ionization Energies
1st Energy Level
578.00 kJ/mol
99+
568.00 kJ/mol
99+
2nd Energy Level
1,158.00 kJ/mol
99+
1,128.00 kJ/mol
99+
3rd Energy Level
2,132.00 kJ/mol
99+
1,814.00 kJ/mol
99+
4th Energy Level
3,493.00 kJ/mol
99+
2,991.00 kJ/mol
99+
Electrochemical Equivalent
3.02 g/amp-hr
17
1.72 g/amp-hr
99+
Electron Work Function
Not Available
Not Available
Other Chemical Properties
Ionization, Radioactive Isotopes, Radioactivity, Solubility
Ionization, Radioactive Isotopes, Radioactivity
Atomic Properties
Atomic Number
95
23
91
27
Electron Configuration
[Rn] 5f7 7s2
[Rn] 5f2 6d1 7s2
Crystal Structure
Double Hexagonal Close Packed (DHCP)
Tetragonal (TETR)
Crystal Lattice
DHCP-Crystal-Structure-of-Americium.jpg#100
TETR-Crystal-Structure-of-Protactinium.jpg#100
Atom
Number of Protons
95
23
91
27
Number of Neutrons
148
12
122
21
Number of Electrons
95
23
91
27
Radius of an Atom
Atomic Radius
173.00 pm
21
163.00 pm
25
Covalent Radius
180.00 pm
21
200.00 pm
11
Van der Waals Radius
244.00 pm
10
243.00 pm
11
Atomic Weight
243.00 amu
20
231.04 amu
24
Atomic Volume
17.86 cm3/mol
29
15.00 cm3/mol
34
Adjacent Atomic Numbers
Valence Electron Potential
44.00 (-eV)
40
92.00 (-eV)
11
Lattice Constant
346.81 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
Not Available
Not Available
Mechanical Properties
Density
Density At Room Temperature
12.00 g/cm3
30
15.37 g/cm3
20
Tensile Strength
Not Available
Not Available
Viscosity
Not Available
Not Available
Vapor Pressure
Vapor Pressure at 1000 K
0.00 (Pa)
13
Not Available
Elasticity properties
Poisson Ratio
Not Available
Not Available
Other Mechanical Properties
NA
Unknown
Magnetic Properties
Magnetic Characteristics
Specific Gravity
13.67
15
15.37
12
Magnetic Ordering
Paramagnetic
Paramagnetic
Electrical Properties
Electrical Property
Unknown
Conductor
Resistivity
0.69 nΩ·m
99+
177.00 nΩ·m
21
Electrical Conductivity
0.02 106/cm Ω
99+
0.05 106/cm Ω
34
Thermal Properties
Specific Heat
0.11 J/(kg K)
99+
0.12 J/(kg K)
40
Molar Heat Capacity
62.70 J/mol·K
1
Not Available
Thermal Conductivity
10.00 W/m·K
99+
47.00 W/m·K
32
Critical Temperature
Not Available
Not Available
Thermal Expansion
Not Available
9.90 µm/(m·K)
40
Enthalpy
Enthalpy of Fusion
14.39 kJ/mol
24
12.34 kJ/mol
28
Enthalpy of Atomization
268.00 kJ/mol
40
Not Available
Standard Molar Entropy
Not Available
198.10 J/mol.K
1
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