Symbol
Ca
  
Pa
  
Group Number
Not Available
  
Period Number
4
  
7
  
Block
s block
  
f block
  
Element Family
Alkaline Earth
  
Actinide
  
Space Group Name
Fm_ 3m
  
I4/mmm
  
Interesting Facts
- Calcium ranks 5th rank in the list of earth’s abundance Percentage.
- It is found in the compound state.
- Gypsum or calcium sulfate is used as plaster and plaster of paris.
  
- Protactinium metal has 29 isotopes.
- Isotopes of Protactinium-231 used in nuclear weapon.
  
Sources
Earth's crust, Found in Minerals, Mining, Ores of Minerals
  
Found in Uranium Ores, Mining, Ores of metals
  
History
  
  
Who Discovered
Humphry Davy
  
William Crookes
  
Discovery
In 1808
  
In 1900
  
Abundance
  
  
Abundance In Universe
Not Available
  
Abundance In Sun
~-9999 %
  
Abundance In Meteorites
Not Available
  
Abundance In Earth's Crust
Abundance In Humans
Not Available
  
Uses & Benefits
- It is used as a reducing agent while preparing metals like thorium and uranium. It is also used as an alloying agent for metals such as aluminum, copper & lead.
- Calcium carbonate or lime stone is used in cement.
  
- Currently known uses of Protactinium metal are limited to research purpose only.
  
Industrial Uses
Chemical Industry
  
NA
  
Medical Uses
Dentistry, Pharmaceutical Industry
  
NA
  
Other Uses
Alloys
  
NA
  
Biological Properties
  
  
Toxicity
Non Toxic
  
Highly Toxic
  
Present in Human Body
Yes
  
No
  
In Blood
60.50 Blood/mg dm-3
  
4
0.00 Blood/mg dm-3
  
37
In Bone
170,000.00 p.p.m.
  
1
0.00 p.p.m.
  
36
Melting Point
1,568.00 °C
  
21
Boiling Point
1,484.00 °C
  
99+
4,027.00 °C
  
12
Appearance
  
  
Physical State
Solid
  
Solid
  
Color
Gray
  
Silver
  
Luster
NA
  
Metallic
  
Hardness
  
  
Mohs Hardness
Not Available
  
Brinell Hardness
170.00 MPa
  
99+
Not Available
  
Speed of Sound
3,810.00 m/s
  
19
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 Formula
Ca
  
Pa
  
Isotopes
  
  
Electronegativity
  
  
Pauling Electronegativity
Sanderson Electronegativity
Not Available
  
Allred Rochow Electronegativity
Mulliken-Jaffe Electronegativity
Not Available
  
Allen Electronegativity
Not Available
  
Electropositivity
  
  
Pauling Electropositivity
Ionization Energies
  
  
1st Energy Level
589.80 kJ/mol
  
99+
568.00 kJ/mol
  
99+
2nd Energy Level
1,145.40 kJ/mol
  
99+
1,128.00 kJ/mol
  
99+
3rd Energy Level
4,912.40 kJ/mol
  
7
1,814.00 kJ/mol
  
99+
4th Energy Level
6,491.00 kJ/mol
  
7
2,991.00 kJ/mol
  
99+
5th Energy Level
8,153.00 kJ/mol
  
7
Not Available
  
6th Energy Level
10,496.00 kJ/mol
  
8
Not Available
  
7th Energy level
12,270.00 kJ/mol
  
12
Not Available
  
8th Energy Level
14,206.00 kJ/mol
  
15
Not Available
  
9th Energy Level
18,191.00 kJ/mol
  
12
Not Available
  
10th Energy Level
20,385.00 kJ/mol
  
16
Not Available
  
11th Energy Level
57,110.00 kJ/mol
  
3
Not Available
  
12th Energy Level
63,410.00 kJ/mol
  
3
Not Available
  
13th Energy Level
70,110.00 kJ/mol
  
3
Not Available
  
14th Energy Level
78,890.00 kJ/mol
  
4
Not Available
  
15th Energy Level
86,310.00 kJ/mol
  
5
Not Available
  
16th Energy Level
94,000.00 kJ/mol
  
6
Not Available
  
17th Energy Level
104,900.00 kJ/mol
  
7
Not Available
  
18th Energy Level
111,711.00 kJ/mol
  
8
Not Available
  
Electrochemical Equivalent
0.75 g/amp-hr
  
99+
1.72 g/amp-hr
  
99+
Electron Work Function
Not Available
  
Other Chemical Properties
Chemical Stability, Flammability, Ionization, Solubility
  
Ionization, Radioactive Isotopes, Radioactivity
  
Electron Configuration
[Ar] 4s2
  
[Rn] 5f2 6d1 7s2
  
Crystal Structure
Face Centered Cubic (FCC)
  
Tetragonal (TETR)
  
Crystal Lattice
FCC-Crystal-Structure-of-Calcium.jpg#100
  
TETR-Crystal-Structure-of-Protactinium.jpg#100
  
Atom
  
  
Radius of an Atom
  
  
Atomic Volume
29.90 cm3/mol
  
7
15.00 cm3/mol
  
34
Adjacent Atomic Numbers
  
  
Valence Electron Potential
29.00 (-eV)
  
99+
92.00 (-eV)
  
11
Lattice Angles
π/2, π/2, π/2
  
π/2, π/2, π/2
  
Lattice C/A Ratio
Not Available
  
Not Available
  
Density
  
  
Density At Room Temperature
1.55 g/cm3
  
99+
15.37 g/cm3
  
20
Density When Liquid (at m.p.)
1.38 g/cm3
  
99+
Not Available
  
Tensile Strength
Not Available
  
Not Available
  
Viscosity
Not Available
  
Not Available
  
Vapor Pressure
  
  
Vapor Pressure at 1000 K
Not Available
  
Elasticity properties
  
  
Shear Modulus
Not Available
  
Bulk Modulus
Not Available
  
Young's Modulus
Not Available
  
Poisson Ratio
Not Available
  
Other Mechanical Properties
NA
  
Unknown
  
Magnetic Characteristics
  
  
Magnetic Ordering
Diamagnetic
  
Paramagnetic
  
Electrical Properties
  
  
Electrical Property
Conductor
  
Conductor
  
Resistivity
33.60 nΩ·m
  
99+
177.00 nΩ·m
  
21
Electrical Conductivity
0.30 106/cm Ω
  
6
0.05 106/cm Ω
  
34
Electron Affinity
2.37 kJ/mol
  
39
Not Available
  
Specific Heat
0.63 J/(kg K)
  
7
0.12 J/(kg K)
  
40
Molar Heat Capacity
25.93 J/mol·K
  
34
Not Available
  
Thermal Conductivity
201.00 W/m·K
  
5
47.00 W/m·K
  
32
Critical Temperature
Not Available
  
Not Available
  
Thermal Expansion
22.30 µm/(m·K)
  
19
9.90 µm/(m·K)
  
40
Enthalpy
  
  
Enthalpy of Vaporization
150.00 kJ/mol
  
99+
Not Available
  
Enthalpy of Fusion
8.54 kJ/mol
  
99+
12.34 kJ/mol
  
28
Enthalpy of Atomization
184.00 kJ/mol
  
99+
Not Available
  
Standard Molar Entropy
41.60 J/mol.K
  
36
198.10 J/mol.K
  
1