Symbol
Ra
  
Rb
  
Period Number
7
  
5
  
Block
s block
  
s block
  
Element Family
Alkaline Earth
  
Alkali
  
Space Group Name
Im_ 3m
  
Im_ 3m
  
Interesting Facts
- Radium metal is the heaviest metal of Alkaline earth metals column.
- Radium metal is highly radioactive and does not have any stable isotopes.
  
- Rubidium metal is 16th most common element found in the earth crust.
- Rubidium metal also found in minerals as well as seawater.
  
Sources
Mining, Ores of metals
  
Obtained from Lithium Production.
  
History
  
  
Who Discovered
Not Available
  
Robert Bunsen and Gustav Kirchhoff
  
Discovery
In 1898
  
In 1861
  
Abundance
  
  
Abundance In Universe
Not Available
  
Abundance In Sun
~-9999 %
  
~0.000003 %
  
17
Abundance In Meteorites
Not Available
  
Abundance In Earth's Crust
Uses & Benefits
- It is a highly radioactive metal; and sometime Radium-223 is used to treat prostate cancer.
-
It is used in luminous paints.
  
- 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
NA
  
NA
  
Medical Uses
Pharmaceutical Industry
  
NA
  
Other Uses
NA
  
Alloys, Research Purposes
  
Biological Properties
  
  
Toxicity
Highly Toxic
  
Non Toxic
  
Present in Human Body
No
  
Yes
  
In Blood
Not Available
  
2.49 Blood/mg dm-3
  
7
In Bone
Not Available
  
5.00 p.p.m.
  
13
Boiling Point
1,737.00 °C
  
99+
Appearance
  
  
Physical State
Solid
  
Solid
  
Color
Silvery White
  
Grayish White
  
Luster
Metallic
  
NA
  
Hardness
  
  
Mohs Hardness
Not Available
  
Brinell Hardness
Not Available
  
Speed of Sound
Not Available
  
1,300.00 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
Ra
  
Rb
  
Isotopes
  
  
Electronegativity
  
  
Pauling Electronegativity
Sanderson Electronegativity
Not Available
  
Allred Rochow Electronegativity
Mulliken-Jaffe Electronegativity
Electropositivity
  
  
Pauling Electropositivity
Ionization Energies
  
  
1st Energy Level
509.30 kJ/mol
  
99+
403.00 kJ/mol
  
99+
2nd Energy Level
979.00 kJ/mol
  
99+
2,633.00 kJ/mol
  
6
3rd Energy Level
Not Available
  
3,860.00 kJ/mol
  
11
4th Energy Level
Not Available
  
5,080.00 kJ/mol
  
18
5th Energy Level
Not Available
  
6,850.00 kJ/mol
  
19
6th Energy Level
Not Available
  
8,140.00 kJ/mol
  
20
7th Energy level
Not Available
  
9,570.00 kJ/mol
  
20
8th Energy Level
Not Available
  
13,120.00 kJ/mol
  
17
9th Energy Level
Not Available
  
14,500.00 kJ/mol
  
18
10th Energy Level
Not Available
  
26,740.00 kJ/mol
  
6
Electrochemical Equivalent
4.22 g/amp-hr
  
6
3.19 g/amp-hr
  
14
Electron Work Function
Not Available
  
Other Chemical Properties
Ionization, Radioactive Isotopes, Radioactivity
  
Corrosion, Ionization, Radioactive Isotopes, Radioactivity
  
Electron Configuration
[Rn] 7s2
  
[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
  
  
Radius of an Atom
  
  
Atomic Radius
Not Available
  
Atomic Volume
45.20 cm3/mol
  
4
55.90 cm3/mol
  
2
Adjacent Atomic Numbers
  
  
Valence Electron Potential
20.10 (-eV)
  
99+
9.47 (-eV)
  
99+
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
5.50 g/cm3
  
99+
1.53 g/cm3
  
99+
Density When Liquid (at m.p.)
Not Available
  
1.46 g/cm3
  
99+
Tensile Strength
Not Available
  
Not Available
  
Viscosity
Not Available
  
Not Available
  
Vapor Pressure
  
  
Elasticity properties
  
  
Bulk Modulus
Not Available
  
Young's Modulus
Not Available
  
Poisson Ratio
Not Available
  
Not Available
  
Other Mechanical Properties
NA
  
Ductile
  
Magnetic Characteristics
  
  
Magnetic Ordering
Nonmagnetic
  
Paramagnetic
  
Electrical Properties
  
  
Electrical Property
NA
  
Conductor
  
Resistivity
100.00 nΩ·m
  
31
128.00 nΩ·m
  
26
Electrical Conductivity
Not Available
  
0.08 10
6/cm Ω
  
24
Electron Affinity
Not Available
  
46.90 kJ/mol
  
24
Specific Heat
0.12 J/(kg K)
  
40
0.36 J/(kg K)
  
17
Molar Heat Capacity
Not Available
  
31.06 J/mol·K
  
5
Thermal Conductivity
18.60 W/m·K
  
99+
58.20 W/m·K
  
26
Critical Temperature
Not Available
  
Thermal Expansion
Not Available
  
90.00 µm/(m·K)
  
2
Enthalpy
  
  
Enthalpy of Vaporization
Not Available
  
69.20 kJ/mol
  
99+
Enthalpy of Fusion
Not Available
  
2.19 kJ/mol
  
99+
Enthalpy of Atomization
163.00 kJ/mol
  
99+
82.00 kJ/mol
  
99+
Standard Molar Entropy
71.00 J/mol.K
  
14
76.80 J/mol.K
  
5