Symbol
K
  
Hf
  
Period Number
4
  
6
  
Block
s block
  
d block
  
Element Family
Alkali
  
Transition Metal
  
Space Group Name
Im_ 3m
  
P63/mmc
  
Interesting Facts
- In the list of most abundant element Potassium is ranked 7th.
- Potassium can easily be sliced (chopped) down using knife.
  
- Hafnium metal is highly reactive, hence not found free in nature.
- Hafnium metal as predicated after Mendeleev finished his periodic table.
  
Sources
Found in Minerals, Mining
  
By-product Zirconium Refining
  
History
  
  
Who Discovered
Humphry Davy
  
Dirk Coster and George de Hevesy
  
Discovery
In 1807
  
In 1922
  
Abundance
  
  
Abundance In Sun
~0.0000001 %
  
26
Abundance In Earth's Crust
Abundance In Humans
Not Available
  
Uses & Benefits
- 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.
  
- It has an ability to absorb neutrons and hence it is used to make control rods in nuclear submarines. And this metal is also used in Plasma welding torches.
-
It alloys with iron, titanium and niobium are very useful.
  
Industrial Uses
Ammunition Industry, Chemical Industry
  
Ammunition Industry
  
Medical Uses
Pharmaceutical Industry
  
NA
  
Other Uses
NA
  
Alloys, In Nuclear Reactors, Nuclear Research, Research Purposes
  
Biological Properties
  
  
Toxicity
Toxic
  
Toxic
  
Present in Human Body
Yes
  
No
  
In Blood
1,620.00 Blood/mg dm-3
  
2
Not Available
  
In Bone
2,100.00 p.p.m.
  
3
Not Available
  
Melting Point
2,150.00 °C
  
10
Appearance
  
  
Physical State
Solid
  
Solid
  
Color
Silvery Gray
  
Gray
  
Luster
NA
  
Metallic
  
Hardness
  
  
Brinell Hardness
1,450.00 MPa
  
6
Vickers Hardness
Not Available
  
1,520.00 MPa
  
5
Speed of Sound
2,000.00 m/s
  
99+
3,010.00 m/s
  
27
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
K
  
Hf
  
Isotopes
  
  
Electronegativity
  
  
Pauling Electronegativity
Sanderson Electronegativity
Not Available
  
Allred Rochow Electronegativity
Mulliken-Jaffe Electronegativity
Not Available
  
Electropositivity
  
  
Pauling Electropositivity
Ionization Energies
  
  
1st Energy Level
418.80 kJ/mol
  
99+
658.50 kJ/mol
  
40
2nd Energy Level
3,052.00 kJ/mol
  
5
1,440.00 kJ/mol
  
99+
3rd Energy Level
4,420.00 kJ/mol
  
8
2,250.00 kJ/mol
  
99+
4th Energy Level
5,877.00 kJ/mol
  
9
3,216.00 kJ/mol
  
99+
5th Energy Level
7,975.00 kJ/mol
  
8
Not Available
  
6th Energy Level
9,590.00 kJ/mol
  
13
Not Available
  
7th Energy level
11,343.00 kJ/mol
  
17
Not Available
  
8th Energy Level
14,944.00 kJ/mol
  
13
Not Available
  
9th Energy Level
16,963.70 kJ/mol
  
15
Not Available
  
10th Energy Level
48,610.00 kJ/mol
  
3
Not Available
  
11th Energy Level
54,490.00 kJ/mol
  
4
Not Available
  
12th Energy Level
60,730.00 kJ/mol
  
4
Not Available
  
13th Energy Level
68,950.00 kJ/mol
  
4
Not Available
  
14th Energy Level
75,900.00 kJ/mol
  
5
Not Available
  
15th Energy Level
83,080.00 kJ/mol
  
6
Not Available
  
16th Energy Level
93,400.00 kJ/mol
  
7
Not Available
  
17th Energy Level
99,710.00 kJ/mol
  
8
Not Available
  
Electrochemical Equivalent
1.46 g/amp-hr
  
99+
1.66 g/amp-hr
  
99+
Other Chemical Properties
Chemical Stability, Flammability, Ionization, Solubility
  
Anti Corrosion, Ionization, Radioactive Isotopes, Solubility
  
Electron Configuration
[Ar] 4s1
  
[Xe] 4f14 5d2 6s2
  
Crystal Structure
Body Centered Cubic (BCC)
  
Hexagonal Close Packed (HCP)
  
Crystal Lattice
BCC-Crystal-Structure-.jpg#100
  
BCC-Crystal-Structure-.jpg#100
  
Atom
  
  
Radius of an Atom
  
  
Atomic Volume
45.46 cm3/mol
  
3
13.60 cm3/mol
  
38
Adjacent Atomic Numbers
  
  
Valence Electron Potential
10.40 (-eV)
  
99+
81.00 (-eV)
  
16
Lattice Angles
π/2, π/2, π/2
  
π/2, π/2, 2 π/3
  
Lattice C/A Ratio
Not Available
  
Density
  
  
Density At Room Temperature
0.86 g/cm3
  
99+
13.31 g/cm3
  
26
Density When Liquid (at m.p.)
0.83 g/cm3
  
99+
12.00 g/cm3
  
12
Tensile Strength
Not Available
  
Viscosity
Not Available
  
Not Available
  
Vapor Pressure
  
  
Vapor Pressure at 2000 K
Not Available
  
Elasticity properties
  
  
Poisson Ratio
Not Available
  
Other Mechanical Properties
NA
  
Ductile, Malleable
  
Magnetic Characteristics
  
  
Magnetic Ordering
Paramagnetic
  
Paramagnetic
  
Electrical Properties
  
  
Electrical Property
Conductor
  
Conductor
  
Resistivity
331.00 nΩ·m
  
14
Electrical Conductivity
0.14 106/cm Ω
  
14
0.03 106/cm Ω
  
39
Electron Affinity
48.40 kJ/mol
  
22
0.00 kJ/mol
  
40
Specific Heat
0.75 J/(kg K)
  
6
0.14 J/(kg K)
  
37
Molar Heat Capacity
29.60 J/mol·K
  
6
25.73 J/mol·K
  
36
Thermal Conductivity
102.50 W/m·K
  
15
23.00 W/m·K
  
99+
Critical Temperature
Not Available
  
Thermal Expansion
83.30 µm/(m·K)
  
3
5.90 µm/(m·K)
  
99+
Enthalpy
  
  
Enthalpy of Vaporization
77.50 kJ/mol
  
99+
661.10 kJ/mol
  
5
Enthalpy of Fusion
2.32 kJ/mol
  
99+
25.10 kJ/mol
  
8
Enthalpy of Atomization
89.50 kJ/mol
  
99+
703.00 kJ/mol
  
5
Standard Molar Entropy
64.70 J/mol.K
  
18
43.60 J/mol.K
  
34