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Rubidium vs Francium

Rubidium
Francium
Francium vs Rubidium


Periodic Table
Symbol
Rb   
Fr   
Group Number
1   
17
1   
17
Period Number
5   
7   
Block
s block   
s block   
Element Family
Alkali   
Alkali   
CAS Number
7440177   
99+
7440735   
18
Space Group Name
Im_ 3m   
Not Available   
Space Group Number
229.00   
1
Not Available   
Facts
Interesting Facts
  • Rubidium metal is 16th most common element found in the earth crust.
  • Rubidium metal also found in minerals as well as seawater.
  
  • 223 Francium has the longest half life at 21.8.
  • Francium metal is produced by alpha decay in 227Actinium 227.
  
Sources
Obtained from Lithium Production.   
Formed by Decay Process, Mining   
History
  
  
Who Discovered
Robert Bunsen and Gustav Kirchhoff   
Marguerite Perey   
Discovery
In 1861   
In 1939   
Abundance
  
  
Abundance In Universe
1 * 10-6 %   
16
Not Available   
Abundance In Sun
~0.000003 %   
17
~-9999 %   
Abundance In Meteorites
0.00 %   
19
Not Available   
Abundance In Earth's Crust
0.01 %   
18
Not Available   
Abundance In Oceans
0.00 %   
7
Not Available   
Abundance In Humans
0.00 %   
7
Not Available   
Uses
Uses & Benefits
  • Rubidium's main application is in the glass manufacturing.
  • Rubidium can very easily get ionized and hence it is used for ion engines, but it is still less efficient than that of Caesium.
  
  • Francium has no known uses as it has a half life of only 22 minutes.
  
Industrial Uses
NA   
NA   
Medical Uses
NA   
NA   
Other Uses
Alloys, Research Purposes   
NA   
Biological Properties
  
  
Toxicity
Non Toxic   
NA   
Present in Human Body
Yes   
No   
In Blood
2.49 Blood/mg dm-3   
7
0.00 Blood/mg dm-3   
37
In Bone
5.00 p.p.m.   
13
0.00 p.p.m.   
36
Physical Properties
Melting Point
38.89 °C   
99+
27.00 °C   
99+
Boiling Point
688.00 °C   
99+
677.00 °C   
99+
Appearance
  
  
Physical State
Solid   
Solid   
Color
Grayish White   
NA   
Luster
NA   
NA   
Hardness
  
  
Mohs Hardness
0.30   
24
Not Available   
Brinell Hardness
0.22 MPa   
99+
Not Available   
Speed of Sound
1,300.00 m/s   
99+
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
Rb   
Fr   
Isotopes
  
  
Known Isotopes
29   
10
33   
6
Electronegativity
  
  
Pauling Electronegativity
0.82   
99+
0.70   
99+
Sanderson Electronegativity
0.31   
32
Not Available   
Allred Rochow Electronegativity
0.89   
40
0.86   
99+
Mulliken-Jaffe Electronegativity
0.69   
24
0.68   
25
Allen Electronegativity
0.71   
99+
0.67   
99+
Electropositivity
  
  
Pauling Electropositivity
3.18   
3
3.30   
1
Ionization Energies
  
  
1st Energy Level
403.00 kJ/mol   
99+
380.00 kJ/mol   
99+
2nd Energy Level
2,633.00 kJ/mol   
6
Not Available   
3rd Energy Level
3,860.00 kJ/mol   
11
Not Available   
4th Energy Level
5,080.00 kJ/mol   
18
Not Available   
5th Energy Level
6,850.00 kJ/mol   
19
Not Available   
6th Energy Level
8,140.00 kJ/mol   
20
Not Available   
7th Energy level
9,570.00 kJ/mol   
20
Not Available   
8th Energy Level
13,120.00 kJ/mol   
17
Not Available   
9th Energy Level
14,500.00 kJ/mol   
18
Not Available   
10th Energy Level
26,740.00 kJ/mol   
6
Not Available   
Electrochemical Equivalent
3.19 g/amp-hr   
14
8.32 g/amp-hr   
1
Electron Work Function
2.16 eV   
99+
Not Available   
Other Chemical Properties
Corrosion, Ionization, Radioactive Isotopes, Radioactivity   
Ionization, Radioactive Isotopes, Radioactivity, Solubility   
Atomic Properties
Atomic Number
37   
99+
87   
31
Electron Configuration
[Kr] 5s1   
[Rn] 7s1   
Crystal Structure
Body Centered Cubic (BCC)   
Body Centered Cubic (BCC)   
Crystal Lattice
BCC-Crystal-Structure-.jpg#100   
BCC-Crystal-Structure-.jpg#100   
Atom
  
  
Number of Protons
37   
99+
87   
31
Number of Neutrons
48   
99+
136   
17
Number of Electrons
37   
99+
87   
31
Radius of an Atom
  
  
Atomic Radius
248.00 pm   
2
Not Available   
Covalent Radius
220.00 pm   
4
260.00 pm   
1
Van der Waals Radius
303.00 pm   
3
348.00 pm   
1
Atomic Weight
85.47 amu   
99+
223.00 amu   
27
Atomic Volume
55.90 cm3/mol   
2
Not Available   
Adjacent Atomic Numbers
  
  
Previous Element
Gallium
  
Polonium
  
Next Element
Strontium
  
Radium
  
Valence Electron Potential
9.47 (-eV)   
99+
8.00 (-eV)   
99+
Lattice Constant
558.50 pm   
10
Not Available   
Lattice Angles
π/2, π/2, π/2   
NA   
Lattice C/A Ratio
Not Available   
Not Available   
Mechanical Properties
Density
  
  
Density At Room Temperature
1.53 g/cm3   
99+
1.87 g/cm3   
99+
Density When Liquid (at m.p.)
1.46 g/cm3   
99+
Not Available   
Tensile Strength
Not Available   
Not Available   
Viscosity
Not Available   
Not Available   
Vapor Pressure
  
  
Elasticity properties
  
  
Bulk Modulus
2.50 GPa   
99+
Not Available   
Young's Modulus
2.40 GPa   
99+
Not Available   
Poisson Ratio
Not Available   
Not Available   
Other Mechanical Properties
Ductile   
NA   
Magnetic Properties
Magnetic Characteristics
  
  
Specific Gravity
1.53   
99+
Not Available   
Magnetic Ordering
Paramagnetic   
Paramagnetic   
Electrical Properties
  
  
Electrical Property
Conductor   
Poor Conductor   
Resistivity
128.00 nΩ·m   
26
3.00 nΩ·m   
99+
Electrical Conductivity
0.08 106/cm Ω   
24
0.03 106/cm Ω   
40
Electron Affinity
46.90 kJ/mol   
24
Not Available   
Thermal Properties
Specific Heat
0.36 J/(kg K)   
17
Not Available   
Molar Heat Capacity
31.06 J/mol·K   
5
Not Available   
Thermal Conductivity
58.20 W/m·K   
26
15.00 W/m·K   
99+
Critical Temperature
2,093.00 K   
4
Not Available   
Thermal Expansion
90.00 µm/(m·K)   
2
Not Available   
Enthalpy
  
  
Enthalpy of Vaporization
69.20 kJ/mol   
99+
Not Available   
Enthalpy of Fusion
2.19 kJ/mol   
99+
Not Available   
Enthalpy of Atomization
82.00 kJ/mol   
99+
71.00 kJ/mol   
99+
Standard Molar Entropy
76.80 J/mol.K   
5
Not Available   
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