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Rubidium Potassium Comparison


Potassium Rubidium comparison


Periodic Table

Symbol
Rb   
K   

Group Number
1   
17
1   
17

Period Number
5   
4   

Block
s block   
s block   

Element Family
Alkali   
Alkali   

CAS Number
7440177   
99+
7440097   
99+

Space Group Name
Im_ 3m   
Im_ 3m   

Space Group Number
229.00   
1
229.00   
1

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.
  
  • In the list of most abundant element Potassium is ranked 7th.
  • Potassium can easily be sliced (chopped) down using knife.
  

Sources
Obtained from Lithium Production.   
Found in Minerals, Mining   

History
  
  

Who Discovered
Robert Bunsen and Gustav Kirchhoff   
Humphry Davy   

Discovery
In 1861   
In 1807   

Abundance
  
  

Abundance In Universe
1 * 10-6 %   
16
3 * 10-4 %   
9

Abundance In Sun
~0.000003 %   
17
~0.0004 %   
9

Abundance In Meteorites
0.00 %   
19
0.07 %   
9

Abundance In Earth's Crust
0.01 %   
18
1.50 %   
6

Abundance In Oceans
0.00 %   
7
0.04 %   
3

Abundance In Humans
0.00 %   
7
0.20 %   
2

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.
  
  • 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
Alloys, Research Purposes   
NA   

Biological Properties
  
  

Toxicity
Non Toxic   
Toxic   

Present in Human Body
Yes   
Yes   

In Blood
2.49 Blood/mg dm-3   
7
1,620.00 Blood/mg dm-3   
2

In Bone
5.00 p.p.m.   
13
2,100.00 p.p.m.   
3

Physical Properties

Melting Point
38.89 °C   
99+
63.65 °C   
99+

Boiling Point
688.00 °C   
99+
774.00 °C   
99+

Appearance
  
  

Physical State
Solid   
Solid   

Color
Grayish White   
Silvery Gray   

Luster
NA   
NA   

Hardness
  
  

Mohs Hardness
0.30   
24
0.40   
23

Brinell Hardness
0.22 MPa   
99+
0.36 MPa   
99+

Speed of Sound
1,300.00 m/s   
99+
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 Properties

Chemical Formula
Rb   
K   

Isotopes
  
  

Known Isotopes
29   
10
20   
19

Electronegativity
  
  

Pauling Electronegativity
0.82   
99+
0.82   
99+

Sanderson Electronegativity
0.31   
32
0.45   
31

Allred Rochow Electronegativity
0.89   
40
0.91   
39

Mulliken-Jaffe Electronegativity
0.69   
24
0.73   
23

Allen Electronegativity
0.71   
99+
0.73   
99+

Electropositivity
  
  

Pauling Electropositivity
3.18   
3
3.18   
3

Ionization Energies
  
  

1st Energy Level
403.00 kJ/mol   
99+
418.80 kJ/mol   
99+

2nd Energy Level
2,633.00 kJ/mol   
6
3,052.00 kJ/mol   
5

3rd Energy Level
3,860.00 kJ/mol   
11
4,420.00 kJ/mol   
8

4th Energy Level
5,080.00 kJ/mol   
18
5,877.00 kJ/mol   
9

5th Energy Level
6,850.00 kJ/mol   
19
7,975.00 kJ/mol   
8

6th Energy Level
8,140.00 kJ/mol   
20
9,590.00 kJ/mol   
13

7th Energy level
9,570.00 kJ/mol   
20
11,343.00 kJ/mol   
17

8th Energy Level
13,120.00 kJ/mol   
17
14,944.00 kJ/mol   
13

9th Energy Level
14,500.00 kJ/mol   
18
16,963.70 kJ/mol   
15

10th Energy Level
26,740.00 kJ/mol   
6
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
3.19 g/amp-hr   
14
1.46 g/amp-hr   
99+

Electron Work Function
2.16 eV   
99+
2.30 eV   
99+

Other Chemical Properties
Corrosion, Ionization, Radioactive Isotopes, Radioactivity   
Chemical Stability, Flammability, Ionization, Solubility   

Atomic Properties

Atomic Number
37   
99+
19   
99+

Electron Configuration
[Kr] 5s1   
[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
  
  

Number of Protons
37   
99+
19   
99+

Number of Neutrons
48   
99+
20   
99+

Number of Electrons
37   
99+
19   
99+

Radius of an Atom
  
  

Atomic Radius
248.00 pm   
2
227.00 pm   
3

Covalent Radius
220.00 pm   
4
203.00 pm   
9

Van der Waals Radius
303.00 pm   
3
275.00 pm   
5

Atomic Weight
85.47 amu   
99+
39.10 amu   
99+

Atomic Volume
55.90 cm3/mol   
2
45.46 cm3/mol   
3

Adjacent Atomic Numbers
  
  

Previous Element
Gallium
  
Aluminium
  

Next Element
Strontium
  
Calcium
  

Valence Electron Potential
9.47 (-eV)   
99+
10.40 (-eV)   
99+

Lattice Constant
558.50 pm   
10
532.80 pm   
12

Lattice Angles
π/2, π/2, π/2   
π/2, π/2, π/2   

Lattice C/A Ratio
Not Available   
Not Available   

Mechanical Properties

Density
  
  

Density At Room Temperature
1.53 g/cm3   
99+
0.86 g/cm3   
99+

Density When Liquid (at m.p.)
1.46 g/cm3   
99+
0.83 g/cm3   
99+

Tensile Strength
Not Available   
Not Available   

Viscosity
Not Available   
Not Available   

Vapor Pressure
  
  

Elasticity properties
  
  

Shear Modulus
Not Available   
1.30 GPa   
99+

Bulk Modulus
2.50 GPa   
99+
3.10 GPa   
99+

Young's Modulus
2.40 GPa   
99+
3.53 GPa   
99+

Poisson Ratio
Not Available   
Not Available   

Other Mechanical Properties
Ductile   
NA   

Magnetic Properties

Magnetic Characteristics
  
  

Specific Gravity
1.53   
99+
0.86   
99+

Magnetic Ordering
Paramagnetic   
Paramagnetic   

Electrical Properties
  
  

Electrical Property
Conductor   
Conductor   

Resistivity
128.00 nΩ·m   
26
72.00 nΩ·m   
37

Electrical Conductivity
0.08 106/cm Ω   
24
0.14 106/cm Ω   
14

Electron Affinity
46.90 kJ/mol   
24
48.40 kJ/mol   
22

Thermal Properties

Specific Heat
0.36 J/(kg K)   
17
0.75 J/(kg K)   
6

Molar Heat Capacity
31.06 J/mol·K   
5
29.60 J/mol·K   
6

Thermal Conductivity
58.20 W/m·K   
26
102.50 W/m·K   
15

Critical Temperature
2,093.00 K   
4
2,223.00 K   
3

Thermal Expansion
90.00 µm/(m·K)   
2
83.30 µm/(m·K)   
3

Enthalpy
  
  

Enthalpy of Vaporization
69.20 kJ/mol   
99+
77.50 kJ/mol   
99+

Enthalpy of Fusion
2.19 kJ/mol   
99+
2.32 kJ/mol   
99+

Enthalpy of Atomization
82.00 kJ/mol   
99+
89.50 kJ/mol   
99+

Standard Molar Entropy
76.80 J/mol.K   
5
64.70 J/mol.K   
18

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