Lead vs Chromium
Periodic Table
Symbol
Pb
Cr
Group Number
14
4
6
12
Period Number
6
4
Block
p block
d block
Element Family
Post-Transition
Transition Metal
CAS Number
7439921
99+
7440473
39
Space Group Name
Fm_ 3m
Im_ 3m
Space Group Number
225.00
2
229.00
1
Facts
Interesting Facts
- Galena mineral contains almost 87% of Lead metal in it, Galena is sulfide mineral.
- The best available source of Lead metal today is by recycling automobile batteries.
- Chromium is highly reactive, hence it is not found free in nature.
- Ores of Chromites mineral are the major source of Chromium metal.
- Almost 90% leather tanning is done with the help of chromium.
Sources
Earth's crust, Found in Minerals, Mining, Ores of metals, Ores of Minerals
Found in Minerals, Mining, Ores of metals, Ores of Minerals
History
Who Discovered
Unknown
Louis Nicolas Vauquelin
Discovery
In Middle Easterns (7000 BCE)
In Between 1797 - 1798
Abundance
Abundance In Universe
1 * 10-6 %
16
1.5 * 10-3 %
7
Abundance In Sun
~0.000001 %
18
~0.002 %
7
Abundance In Meteorites
0.00 %
23
0.30 %
7
Abundance In Earth's Crust
0.00 %
26
0.01 %
13
Abundance In Oceans
0.00 %
22
0.00 %
16
Abundance In Humans
0.00 %
8
0.00 %
16
Uses
Uses & Benefits
- It is also used in insecticides, hair dyes and as an anti-knocking additive for petrol. But all these are banned by the government as Lead metal is known for detrimental to health.
- It is used to harden the steel and produces a stainless steel and other various alloys.
- It is also used to give proper finish to polished mirrors. Its chromium plates are used in bathroom fittings.
Industrial Uses
Chemical Industry, Electrical Industry, Electronic Industry
Automobile Industry, Chemical Industry
Medical Uses
Surgical Instruments Manufacturing
NA
Other Uses
Alloys
Alloys
Biological Properties
Toxicity
Toxic
Highly Toxic
Present in Human Body
Yes
Yes
In Blood
0.21 Blood/mg dm-3
11
0.11 Blood/mg dm-3
12
In Bone
30.00 p.p.m.
10
0.33 p.p.m.
21
Physical Properties
Melting Point
327.50 °C
99+
1,857.00 °C
14
Boiling Point
1,740.00 °C
99+
2,672.00 °C
39
Appearance
Physical State
Solid
Solid
Color
Gray
Silver
Luster
Metallic
Metallic
Hardness
Mohs Hardness
1.50
18
8.50
1
Brinell Hardness
38.00 MPa
99+
687.00 MPa
16
Vickers Hardness
Not Available
1,060.00 MPa
10
Speed of Sound
1,190.00 m/s
99+
5,940.00 m/s
5
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
Pb
Cr
Isotopes
Known Isotopes
35
4
21
18
Electronegativity
Pauling Electronegativity
1.87
13
1.66
18
Sanderson Electronegativity
2.29
4
1.66
14
Allred Rochow Electronegativity
1.55
11
1.56
10
Mulliken-Jaffe Electronegativity
2.41
2
Not Available
Allen Electronegativity
1.85
8
1.65
19
Electropositivity
Pauling Electropositivity
1.67
99+
2.34
36
Ionization Energies
1st Energy Level
715.60 kJ/mol
31
26,130.00 kJ/mol
1
2nd Energy Level
1,450.50 kJ/mol
99+
28,750.00 kJ/mol
1
3rd Energy Level
3,081.50 kJ/mol
23
34,230.00 kJ/mol
1
4th Energy Level
4,083.00 kJ/mol
35
37,066.00 kJ/mol
1
5th Energy Level
6,640.00 kJ/mol
20
97,510.00 kJ/mol
1
6th Energy Level
Not Available
105,800.00 kJ/mol
1
7th Energy level
Not Available
114,300.00 kJ/mol
1
8th Energy Level
Not Available
125,300.00 kJ/mol
1
9th Energy Level
Not Available
134,700.00 kJ/mol
1
10th Energy Level
Not Available
144,300.00 kJ/mol
1
11th Energy Level
Not Available
26,130.00 kJ/mol
12
12th Energy Level
Not Available
28,750.00 kJ/mol
13
13th Energy Level
Not Available
34,230.00 kJ/mol
10
14th Energy Level
Not Available
37,066.00 kJ/mol
12
15th Energy Level
Not Available
97,510.00 kJ/mol
1
16th Energy Level
Not Available
105,800.00 kJ/mol
2
17th Energy Level
Not Available
114,300.00 kJ/mol
3
18th Energy Level
Not Available
125,300.00 kJ/mol
4
19th Energy Level
Not Available
134,700.00 kJ/mol
5
20th Energy Level
Not Available
144,300.00 kJ/mol
7
21st Energy Level
Not Available
157,700.00 kJ/mol
7
22nd Energy Level
Not Available
166,090.00 kJ/mol
6
Electrochemical Equivalent
3.87 g/amp-hr
9
0.32 g/amp-hr
99+
Electron Work Function
4.25 eV
21
4.50 eV
14
Other Chemical Properties
Anti Corrosion, Ionization, Radioactive Isotopes
Anti Corrosion, Chemical Stability, Ionization, Radioactive Isotopes, Solubility
Atomic Properties
Atomic Number
82
34
24
99+
Electron Configuration
[Xe] 4f14 5d10 6s2 6p2
[Ar] 3d5 4s1
Crystal Structure
Face Centered Cubic (FCC)
Body Centered Cubic (BCC)
Crystal Lattice
FCC-Crystal-Structure-of-Lead.jpg#100
BCC-Crystal-Structure-.jpg#100
Atom
Number of Protons
82
34
24
99+
Number of Neutrons
125
19
28
99+
Number of Electrons
82
34
24
99+
Radius of an Atom
Atomic Radius
175.00 pm
19
128.00 pm
99+
Covalent Radius
146.00 pm
38
139.00 pm
99+
Van der Waals Radius
202.00 pm
27
200.00 pm
28
Atomic Weight
207.20 amu
30
52.00 amu
99+
Atomic Volume
18.17 cm3/mol
27
7.23 cm3/mol
99+
Adjacent Atomic Numbers
Valence Electron Potential
24.20 (-eV)
99+
170.00 (-eV)
4
Lattice Constant
495.08 pm
16
291.00 pm
99+
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
11.34 g/cm3
33
7.19 g/cm3
99+
Density When Liquid (at m.p.)
10.66 g/cm3
15
6.30 g/cm3
40
Tensile Strength
12.00 MPa
20
689.00 MPa
7
Viscosity
Not Available
Not Available
Vapor Pressure
Vapor Pressure at 1000 K
1.64 (Pa)
7
0.00 (Pa)
24
Vapor Pressure at 2000 K
Not Available
774.00 (Pa)
1
Elasticity properties
Shear Modulus
5.60 GPa
99+
115.00 GPa
9
Bulk Modulus
46.00 GPa
24
160.00 GPa
11
Young's Modulus
16.00 GPa
99+
279.00 GPa
8
Poisson Ratio
0.44
3
0.21
32
Other Mechanical Properties
Ductile, Malleable
NA
Magnetic Properties
Magnetic Characteristics
Specific Gravity
11.35
25
7.19
99+
Magnetic Ordering
Diamagnetic
Antiferromagnetic
Electrical Properties
Electrical Property
Poor Conductor
NA
Resistivity
208.00 nΩ·m
16
125.00 nΩ·m
27
Electrical Conductivity
0.05 106/cm Ω
36
0.08 106/cm Ω
25
Electron Affinity
35.10 kJ/mol
28
64.30 kJ/mol
15
Thermal Properties
Specific Heat
0.13 J/(kg K)
39
0.45 J/(kg K)
12
Molar Heat Capacity
26.65 J/mol·K
26
23.35 J/mol·K
99+
Thermal Conductivity
35.30 W/m·K
38
93.90 W/m·K
17
Critical Temperature
Not Available
Not Available
Thermal Expansion
28.90 µm/(m·K)
13
4.90 µm/(m·K)
99+
Enthalpy
Enthalpy of Vaporization
179.40 kJ/mol
99+
348.80 kJ/mol
24
Enthalpy of Fusion
4.77 kJ/mol
99+
15.31 kJ/mol
20
Enthalpy of Atomization
194.60 kJ/mol
99+
397.50 kJ/mol
21
Standard Molar Entropy
64.80 J/mol.K
17
23.80 J/mol.K
99+
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