Aug 13 2013
Topics Covered
Introduction
Chemical Properties
Physical Properties
Mechanical Properties
Thermal Properties
Applications
Introduction
Silver is a chemical element with Ag as its symbol. It belongs to group 11 of the periodic table and its atomic number is 47.
Silver is lustrous, soft, very ductile and malleable metal. It has the highest electrical conductivity of all metals, but it is not widely used for electrical purposes as it is very expensive. Silver is not a chemically active metal; however nitric acid and hot concentrated sulfuric acid will react with it.
Silver can be obtained from pure deposits as well as from silver ores such as horn silver and argentite. It can also be obtained as a by-product along with deposits of ores containing gold, copper, or lead.
Silver does not oxidize in air; however it reacts with hydrogen sulfide in the air, causing the metal to tarnish due to the formation of silver sulfide. Hence silver products require regular cleaning. Silver is stable in water.
Chemical Properties
The chemical properties of silver are provided in the table below.
|
Chemical Data |
|
CAS number |
7440-22-4 |
|
Thermal neutron cross section |
63 barns/atom |
|
Electrode potential |
0.799 V |
|
Ionic radius |
0.89 Å |
|
Electronegativity |
1.93 |
|
X-ray absorption edge |
0.4858 Å |
|
Electrochemical equivalent |
4.025 g/A/h |
Physical Properties
The following table discusses the physical properties of silver.
|
Properties |
Metric |
Imperial |
|
Density |
10.50 g/cm3 |
0.379 lb/in3 |
|
Melting point |
962°C |
1764°F |
|
Boiling point |
2212°C |
4014°F |
Mechanical Properties
The mechanical properties of silver are tabulated below.
|
Properties |
Metric |
Imperial |
|
Tensile strength |
140 MPa |
20300 psi |
|
Poisson’s ratio |
0.37 |
0.37 |
|
Modulus of elasticity |
76 GPa |
11000 ksi |
|
Shear modulus |
27.8 GPa |
4030 ksi |
|
Hardness, Vickers |
25 |
25 |
Thermal Properties
The thermal properties of silver are tabulated below.
|
Properties |
Metric |
Imperial |
|
Thermal expansion co-efficient (@20-100°C/68-212°F) |
19.6 µm/m°C |
10.9 µin/in°F |
|
Thermal conductivity |
419 W/mK |
2910 BTU in/hr.ft².°F |
Applications
The following are the application areas of silver:
-
In photography
-
In dentistry
-
As cutlery and mirrors
-
As a catalyst in oxidation reactions
-
In high-capacity zinc long-life batteries
-
As a precious metal to make coins and jewelry
-
In electrical and electronic industries for items such as printed circuits and computer keyboards