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Francium vs Rubidium

Francium
Rubidium
Rubidium vs Francium


Periodic Table
Symbol
Fr  
Rb  
Group Number
1  
17
1  
17
Period Number
7  
5  
Block
s block  
s block  
Element Family
Alkali  
Alkali  
CAS Number
7440735  
18
7440177  
99+
Space Group Name
-  
Im_ 3m  
Space Group Number
225.00  
3
229.00  
2
Facts
Interesting Facts
  • 223 Francium has the longest half life at 21.8.
  • Francium metal is produced by alpha decay in 227Actinium 227.
  
  • Rubidium metal is 16th most common element found in the earth crust.
  • Rubidium metal also found in minerals as well as seawater.
  
Sources
Formed by Decay Process, Mining  
Obtained from Lithium Production.  
History
  
  
Who Discovered
Marguerite Perey  
Robert Bunsen and Gustav Kirchhoff  
Discovery
In 1939  
In 1861  
Abundance
  
  
Abundance In Universe
0.00 %  
40
0.00 %  
17
Abundance In Sun
0.00 %  
30
0.00 %  
17
Abundance In Meteorites
0.00 %  
99+
0.00 %  
19
Abundance In Earth's Crust
0.00 %  
99+
0.01 %  
18
Abundance In Oceans
-  
0.00 %  
7
Abundance In Humans
0.00 %  
24
0.00 %  
8
Uses
Uses & Benefits
  • Francium has no known uses as it has a half life of only 22 minutes.
  
  • 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.
  
Industrial Uses
-  
-  
Medical Uses
-  
-  
Other Uses
-  
Alloys, Research Purposes  
Biological Properties
  
  
Toxicity
-  
Non Toxic  
Present in Human Body
No  
Yes  
In Blood
0.00 Blood/mg dm-3  
40
2.49 Blood/mg dm-3  
7
In Bone
0.00 p.p.m.  
99+
5.00 p.p.m.  
13
Physical
Melting Point
27.00 °C  
99+
38.89 °C  
99+
Boiling Point
677.00 °C  
99+
688.00 °C  
99+
Appearance
  
  
Physical State
Solid  
Solid  
Color
-  
Grayish White  
Luster
-  
-  
Hardness
  
  
Mohs Hardness
0.20  
27
0.30  
26
Brinell Hardness
119.00 MPa  
99+
0.22 MPa  
99+
Vickers Hardness
300.00 MPa  
99+
0.22 MPa  
99+
Speed of Sound
2,440.00 m/s  
99+
1,300.00 m/s  
99+
Optical Properties
  
  
Refractive Index
1.70  
27
1.54  
35
Reflectivity
72.00 %  
11
52.00 %  
29
Allotropes
No  
No  
α Allotropes
-  
-  
β Allotropes
-  
-  
γ Allotropes
-  
-  
Chemical
Chemical Formula
Fr  
Rb  
Isotopes
  
  
Known Isotopes
33  
6
29  
10
Electronegativity
  
  
Pauling Electronegativity
0.70  
99+
0.82  
99+
Sanderson Electronegativity
0.70  
99+
0.31  
99+
Allred Rochow Electronegativity
0.86  
99+
0.89  
99+
Mulliken-Jaffe Electronegativity
0.68  
99+
0.69  
99+
Allen Electronegativity
0.67  
99+
0.71  
99+
Electropositivity
  
  
Pauling Electropositivity
3.30  
1
3.18  
3
Ionization Energies
  
  
1st Energy Level
380.00 kJ/mol  
99+
403.00 kJ/mol  
99+
2nd Energy Level
392.80 kJ/mol  
99+
2,633.00 kJ/mol  
6
3rd Energy Level
392.80 kJ/mol  
99+
3,860.00 kJ/mol  
11
4th Energy Level
392.80 kJ/mol  
99+
5,080.00 kJ/mol  
28
5th Energy Level
392.00 kJ/mol  
99+
6,850.00 kJ/mol  
31
6th Energy Level
3,920.00 kJ/mol  
99+
8,140.00 kJ/mol  
31
7th Energy level
3,920.00 kJ/mol  
99+
9,570.00 kJ/mol  
20
8th Energy Level
3,920.00 kJ/mol  
99+
13,120.00 kJ/mol  
17
9th Energy Level
3,920.00 kJ/mol  
99+
14,500.00 kJ/mol  
18
10th Energy Level
392.00 kJ/mol  
99+
26,740.00 kJ/mol  
6
11th Energy Level
392.00 kJ/mol  
99+
4,030.00 kJ/mol  
99+
12th Energy Level
38,000.00 kJ/mol  
23
4,030.00 kJ/mol  
99+
13th Energy Level
3,920.00 kJ/mol  
99+
4,030.00 kJ/mol  
99+
14th Energy Level
380.00 kJ/mol  
99+
4,030.00 kJ/mol  
99+
15th Energy Level
67,700.00 kJ/mol  
32
40,300.00 kJ/mol  
99+
16th Energy Level
39,200.00 kJ/mol  
99+
40,300.00 kJ/mol  
99+
17th Energy Level
392.00 kJ/mol  
99+
403.00 kJ/mol  
99+
18th Energy Level
3,920.00 kJ/mol  
99+
4,030.00 kJ/mol  
99+
19th Energy Level
392.80 kJ/mol  
99+
403.00 kJ/mol  
99+
20th Energy Level
392.00 kJ/mol  
99+
403.00 kJ/mol  
99+
21st Energy Level
392.00 kJ/mol  
99+
403.00 kJ/mol  
99+
22nd Energy Level
392.00 kJ/mol  
99+
403.00 kJ/mol  
99+
23rd Energy Level
392.80 kJ/mol  
99+
403.00 kJ/mol  
99+
24th Energy Level
392.00 kJ/mol  
99+
403.00 kJ/mol  
99+
25th Energy Level
392.00 kJ/mol  
99+
403.00 kJ/mol  
99+
26th Energy Level
392.80 kJ/mol  
99+
403.00 kJ/mol  
99+
27th Energy Level
392.00 kJ/mol  
99+
403.00 kJ/mol  
99+
28th Energy Level
380.00 kJ/mol  
99+
403.00 kJ/mol  
99+
29th Energy Level
392.00 kJ/mol  
99+
403.00 kJ/mol  
99+
30th Energy Level
677.00 kJ/mol  
31
403.00 kJ/mol  
99+
Electrochemical Equivalent
8.32 g/amp-hr  
1
3.19 g/amp-hr  
16
Electron Work Function
4.07 eV  
33
2.16 eV  
99+
Other Chemical Properties
Ionization, Radioactive Isotopes, Radioactivity, Solubility  
Corrosion, Ionization, Radioactive Isotopes, Radioactivity  
Atomic
Atomic Number
87  
31
37  
99+
Electron Configuration
[Rn] 7s1  
[Kr] 5s1  
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
87  
31
37  
99+
Number of Neutrons
136  
18
48  
99+
Number of Electrons
87  
31
37  
99+
Radius of an Atom
  
  
Atomic Radius
348.00 pm  
1
248.00 pm  
3
Covalent Radius
260.00 pm  
1
220.00 pm  
4
Van der Waals Radius
348.00 pm  
1
303.00 pm  
4
Atomic Weight
223.00 amu  
27
85.47 amu  
99+
Atomic Volume
71.00 cm3/mol  
2
55.90 cm3/mol  
3
Adjacent Atomic Numbers
  
  
Previous Element
Polonium
  
Gallium
  
Next Element
Radium
  
Strontium
  
Valence Electron Potential
8.00 (-eV)  
99+
9.47 (-eV)  
99+
Lattice Constant
440.00 pm  
21
558.50 pm  
11
Lattice Angles
-  
π/2, π/2, π/2  
Lattice C/A Ratio
1.56  
99+
1.59  
28
Mechanical
Density
  
  
Density At Room Temperature
1.87 g/cm3  
99+
1.53 g/cm3  
99+
Density When Liquid (at m.p.)
1.87 g/cm3  
99+
1.46 g/cm3  
99+
Tensile Strength
50.00 MPa  
38
30.00 MPa  
99+
Viscosity
0.00  
25
0.00  
23
Vapor Pressure
  
  
Vapor Pressure at 1000 K
0.00 (Pa)  
37
0.00 (Pa)  
37
Vapor Pressure at 2000 K
0.00 (Pa)  
24
0.00 (Pa)  
35
Elasticity properties
  
  
Shear Modulus
3.60 GPa  
99+
2.50 GPa  
99+
Bulk Modulus
6.00 GPa  
99+
2.50 GPa  
99+
Young's Modulus
0.00 GPa  
99+
2.40 GPa  
99+
Poisson Ratio
0.44  
3
0.37  
7
Other Mechanical Properties
-  
Ductile  
Magnetic
Magnetic Characteristics
  
  
Specific Gravity
0.87  
99+
1.53  
99+
Magnetic Ordering
Paramagnetic  
Paramagnetic  
Permeability
0.00 H/m  
13
0.00 H/m  
11
Susceptibility
0.00  
24
0.00  
24
Electrical Properties
  
  
Electrical Property
Poor Conductor  
Conductor  
Resistivity
3.00 nΩ·m  
99+
128.00 nΩ·m  
26
Electrical Conductivity
0.03 106/cm Ω  
99+
0.08 106/cm Ω  
29
Electron Affinity
0.70 kJ/mol  
99+
46.90 kJ/mol  
29
Thermal
Specific Heat
0.15 J/(kg K)  
37
0.36 J/(kg K)  
17
Molar Heat Capacity
27.00 J/mol·K  
29
31.06 J/mol·K  
7
Thermal Conductivity
15.00 W/m·K  
99+
58.20 W/m·K  
26
Critical Temperature
300.00 K  
99+
2,093.00 K  
18
Thermal Expansion
18.90 µm/(m·K)  
25
90.00 µm/(m·K)  
2
Enthalpy
  
  
Enthalpy of Vaporization
67.00 kJ/mol  
99+
69.20 kJ/mol  
99+
Enthalpy of Fusion
2.30 kJ/mol  
99+
2.19 kJ/mol  
99+
Enthalpy of Atomization
71.00 kJ/mol  
99+
82.00 kJ/mol  
99+
Standard Molar Entropy
42.00 J/mol.K  
99+
76.80 J/mol.K  
5
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