Symbol
Fr
  
K
  
Period Number
7
  
4
  
Block
s block
  
s block
  
Element Family
Alkali
  
Alkali
  
Space Group Name
Not Available
  
Im_ 3m
  
Space Group Number
Not Available
  
Interesting Facts
- 223 Francium has the longest half life at 21.8.
- Francium metal is produced by alpha decay in 227Actinium 227.
  
- In the list of most abundant element Potassium is ranked 7th.
- Potassium can easily be sliced (chopped) down using knife.
  
Sources
Formed by Decay Process, Mining
  
Found in Minerals, Mining
  
History
  
  
Who Discovered
Marguerite Perey
  
Humphry Davy
  
Discovery
In 1939
  
In 1807
  
Abundance
  
  
Abundance In Universe
Not Available
  
Abundance In Sun
~-9999 %
  
Abundance In Meteorites
Not Available
  
Abundance In Earth's Crust
Not Available
  
Abundance In Oceans
Not Available
  
Abundance In Humans
Not Available
  
Uses & Benefits
- Francium has no known uses as it has a half life of only 22 minutes.
  
- Potassium’s compounds are in high demand for their application in Fertilizer manufacturing.
- Potassium carbonate is used in glass manufacturing and Potassium carbonate in manufacturing detergent and body wash.
  
Industrial Uses
NA
  
Ammunition Industry, Chemical Industry
  
Medical Uses
NA
  
Pharmaceutical Industry
  
Other Uses
NA
  
NA
  
Biological Properties
  
  
Toxicity
NA
  
Toxic
  
Present in Human Body
No
  
Yes
  
In Blood
0.00 Blood/mg dm-3
  
37
1,620.00 Blood/mg dm-3
  
2
In Bone
0.00 p.p.m.
  
36
2,100.00 p.p.m.
  
3
Appearance
  
  
Physical State
Solid
  
Solid
  
Color
NA
  
Silvery Gray
  
Luster
NA
  
NA
  
Hardness
  
  
Mohs Hardness
Not Available
  
Brinell Hardness
Not Available
  
Speed of Sound
Not Available
  
2,000.00 m/s
  
99+
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
Fr
  
K
  
Isotopes
  
  
Electronegativity
  
  
Pauling Electronegativity
Sanderson Electronegativity
Not Available
  
Allred Rochow Electronegativity
Mulliken-Jaffe Electronegativity
Electropositivity
  
  
Pauling Electropositivity
Ionization Energies
  
  
1st Energy Level
380.00 kJ/mol
  
99+
418.80 kJ/mol
  
99+
2nd Energy Level
Not Available
  
3,052.00 kJ/mol
  
5
3rd Energy Level
Not Available
  
4,420.00 kJ/mol
  
8
4th Energy Level
Not Available
  
5,877.00 kJ/mol
  
9
5th Energy Level
Not Available
  
7,975.00 kJ/mol
  
8
6th Energy Level
Not Available
  
9,590.00 kJ/mol
  
13
7th Energy level
Not Available
  
11,343.00 kJ/mol
  
17
8th Energy Level
Not Available
  
14,944.00 kJ/mol
  
13
9th Energy Level
Not Available
  
16,963.70 kJ/mol
  
15
10th Energy Level
Not Available
  
48,610.00 kJ/mol
  
3
11th Energy Level
Not Available
  
54,490.00 kJ/mol
  
4
12th Energy Level
Not Available
  
60,730.00 kJ/mol
  
4
13th Energy Level
Not Available
  
68,950.00 kJ/mol
  
4
14th Energy Level
Not Available
  
75,900.00 kJ/mol
  
5
15th Energy Level
Not Available
  
83,080.00 kJ/mol
  
6
16th Energy Level
Not Available
  
93,400.00 kJ/mol
  
7
17th Energy Level
Not Available
  
99,710.00 kJ/mol
  
8
Electrochemical Equivalent
8.32 g/amp-hr
  
1
1.46 g/amp-hr
  
99+
Electron Work Function
Not Available
  
Other Chemical Properties
Ionization, Radioactive Isotopes, Radioactivity, Solubility
  
Chemical Stability, Flammability, Ionization, Solubility
  
Electron Configuration
[Rn] 7s1
  
[Ar] 4s1
  
Crystal Structure
Body Centered Cubic (BCC)
  
Body Centered Cubic (BCC)
  
Crystal Lattice
BCC-Crystal-Structure-.jpg#100
  
BCC-Crystal-Structure-.jpg#100
  
Atom
  
  
Radius of an Atom
  
  
Atomic Radius
Not Available
  
Atomic Volume
Not Available
  
45.46 cm3/mol
  
3
Adjacent Atomic Numbers
  
  
Valence Electron Potential
8.00 (-eV)
  
99+
10.40 (-eV)
  
99+
Lattice Constant
Not Available
  
Lattice Angles
NA
  
π/2, π/2, π/2
  
Lattice C/A Ratio
Not Available
  
Not Available
  
Density
  
  
Density At Room Temperature
1.87 g/cm3
  
99+
0.86 g/cm3
  
99+
Density When Liquid (at m.p.)
Not Available
  
0.83 g/cm3
  
99+
Tensile Strength
Not Available
  
Not Available
  
Viscosity
Not Available
  
Not Available
  
Vapor Pressure
  
  
Elasticity properties
  
  
Shear Modulus
Not Available
  
Bulk Modulus
Not Available
  
Young's Modulus
Not Available
  
Poisson Ratio
Not Available
  
Not Available
  
Other Mechanical Properties
NA
  
NA
  
Magnetic Characteristics
  
  
Specific Gravity
Not Available
  
Magnetic Ordering
Paramagnetic
  
Paramagnetic
  
Electrical Properties
  
  
Electrical Property
Poor Conductor
  
Conductor
  
Electrical Conductivity
0.03 106/cm Ω
  
40
0.14 106/cm Ω
  
14
Electron Affinity
Not Available
  
48.40 kJ/mol
  
22
Specific Heat
Not Available
  
0.75 J/(kg K)
  
6
Molar Heat Capacity
Not Available
  
29.60 J/mol·K
  
6
Thermal Conductivity
15.00 W/m·K
  
99+
102.50 W/m·K
  
15
Critical Temperature
Not Available
  
Thermal Expansion
Not Available
  
83.30 µm/(m·K)
  
3
Enthalpy
  
  
Enthalpy of Vaporization
Not Available
  
77.50 kJ/mol
  
99+
Enthalpy of Fusion
Not Available
  
2.32 kJ/mol
  
99+
Enthalpy of Atomization
71.00 kJ/mol
  
99+
89.50 kJ/mol
  
99+
Standard Molar Entropy
Not Available
  
64.70 J/mol.K
  
18