Symbol
Ca
  
Rb
  
Period Number
4
  
5
  
Block
s block
  
s block
  
Element Family
Alkaline Earth
  
Alkali
  
Space Group Name
Fm_ 3m
  
Im_ 3m
  
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.
  
- Rubidium metal is 16th most common element found in the earth crust.
- Rubidium metal also found in minerals as well as seawater.
  
Sources
Earth's crust, Found in Minerals, Mining, Ores of Minerals
  
Obtained from Lithium Production.
  
History
  
  
Who Discovered
Humphry Davy
  
Robert Bunsen and Gustav Kirchhoff
  
Discovery
In 1808
  
In 1861
  
Abundance
  
  
Abundance In Sun
~0.000003 %
  
17
Abundance In Earth's Crust
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.
  
- 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
Chemical Industry
  
NA
  
Medical Uses
Dentistry, Pharmaceutical Industry
  
NA
  
Other Uses
Alloys
  
Alloys, Research Purposes
  
Biological Properties
  
  
Toxicity
Non Toxic
  
Non Toxic
  
Present in Human Body
Yes
  
Yes
  
In Blood
60.50 Blood/mg dm-3
  
4
2.49 Blood/mg dm-3
  
7
In Bone
170,000.00 p.p.m.
  
1
5.00 p.p.m.
  
13
Boiling Point
1,484.00 °C
  
99+
Appearance
  
  
Physical State
Solid
  
Solid
  
Color
Gray
  
Grayish White
  
Luster
NA
  
NA
  
Hardness
  
  
Brinell Hardness
170.00 MPa
  
99+
Speed of Sound
3,810.00 m/s
  
19
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
Ca
  
Rb
  
Isotopes
  
  
Electronegativity
  
  
Pauling Electronegativity
Sanderson Electronegativity
Allred Rochow Electronegativity
Mulliken-Jaffe Electronegativity
Electropositivity
  
  
Pauling Electropositivity
Ionization Energies
  
  
1st Energy Level
589.80 kJ/mol
  
99+
403.00 kJ/mol
  
99+
2nd Energy Level
1,145.40 kJ/mol
  
99+
2,633.00 kJ/mol
  
6
3rd Energy Level
4,912.40 kJ/mol
  
7
3,860.00 kJ/mol
  
11
4th Energy Level
6,491.00 kJ/mol
  
7
5,080.00 kJ/mol
  
18
5th Energy Level
8,153.00 kJ/mol
  
7
6,850.00 kJ/mol
  
19
6th Energy Level
10,496.00 kJ/mol
  
8
8,140.00 kJ/mol
  
20
7th Energy level
12,270.00 kJ/mol
  
12
9,570.00 kJ/mol
  
20
8th Energy Level
14,206.00 kJ/mol
  
15
13,120.00 kJ/mol
  
17
9th Energy Level
18,191.00 kJ/mol
  
12
14,500.00 kJ/mol
  
18
10th Energy Level
20,385.00 kJ/mol
  
16
26,740.00 kJ/mol
  
6
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+
3.19 g/amp-hr
  
14
Other Chemical Properties
Chemical Stability, Flammability, Ionization, Solubility
  
Corrosion, Ionization, Radioactive Isotopes, Radioactivity
  
Electron Configuration
[Ar] 4s2
  
[Kr] 5s1
  
Crystal Structure
Face Centered Cubic (FCC)
  
Body Centered Cubic (BCC)
  
Crystal Lattice
FCC-Crystal-Structure-of-Calcium.jpg#100
  
BCC-Crystal-Structure-.jpg#100
  
Atom
  
  
Radius of an Atom
  
  
Atomic Volume
29.90 cm3/mol
  
7
55.90 cm3/mol
  
2
Adjacent Atomic Numbers
  
  
Valence Electron Potential
29.00 (-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
1.55 g/cm3
  
99+
1.53 g/cm3
  
99+
Density When Liquid (at m.p.)
1.38 g/cm3
  
99+
1.46 g/cm3
  
99+
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
  
Poisson Ratio
Not Available
  
Other Mechanical Properties
NA
  
Ductile
  
Magnetic Characteristics
  
  
Magnetic Ordering
Diamagnetic
  
Paramagnetic
  
Electrical Properties
  
  
Electrical Property
Conductor
  
Conductor
  
Resistivity
33.60 nΩ·m
  
99+
128.00 nΩ·m
  
26
Electrical Conductivity
0.30 106/cm Ω
  
6
0.08 106/cm Ω
  
24
Electron Affinity
2.37 kJ/mol
  
39
46.90 kJ/mol
  
24
Specific Heat
0.63 J/(kg K)
  
7
0.36 J/(kg K)
  
17
Molar Heat Capacity
25.93 J/mol·K
  
34
31.06 J/mol·K
  
5
Thermal Conductivity
201.00 W/m·K
  
5
58.20 W/m·K
  
26
Critical Temperature
Not Available
  
Thermal Expansion
22.30 µm/(m·K)
  
19
90.00 µm/(m·K)
  
2
Enthalpy
  
  
Enthalpy of Vaporization
150.00 kJ/mol
  
99+
69.20 kJ/mol
  
99+
Enthalpy of Fusion
8.54 kJ/mol
  
99+
2.19 kJ/mol
  
99+
Enthalpy of Atomization
184.00 kJ/mol
  
99+
82.00 kJ/mol
  
99+
Standard Molar Entropy
41.60 J/mol.K
  
36
76.80 J/mol.K
  
5