Gold is a transition metal element denoted by the symbol Au. It has the atomic number 79 and belongs to group 11 of the periodic table. Gold is a noble metal and often occurs naturally in its native form in rocks, alluvial deposits, etc. In its pure form, gold is a lustrous, reddish-yellow substance that is dense, malleable, and ductile.
One common question that many students get does gold conducts electricity or not. In this article, I will answer your query and will also cover its related topics.
So, does Gold conduct electricity? Yes, Gold is a conductor of electricity like other metals. The delocalized electrons present in the free space surrounding the Gold atoms act as free charge carriers which help in the conduction of electricity when a voltage source is applied. Due to the electric potential, these randomly moving electrons align in one direction to move from negative to the positive end, hence, conducting electricity.
Why Does Gold Conduct Electricity?
Like other metals, gold conducts electricity due to the presence of the sea of delocalized electrons surrounding its atoms.
These are free electrons that are not specifically attached with any atom and are free to move in space around the atoms.
The electronic configuration of gold is [Xe] 4f145d10 6s1. One electron present in the 6s subshell is so far away from the center of the atom that it experiences a negligible binding force from the nucleus and is, therefore, free to move around other atoms as well.
Normally, these delocalized electrons move randomly in space. However, as soon as an electric potential is applied they align themselves in a particular direction and start moving from negative to the positive end.
Is Gold a Good Conductor of Electricity?
Yes, gold is a good conductor of electricity. In terms of electrical conductivity, it stands third after silver and copper.
Gold is easy to use and resistant to tarnishing which is why it is a preferred choice for a number of electrical equipment.
The electrical conductivity of a substance depends upon the availability of the free charge carriers. In metals, the delocalized electrons are responsible for the conduction of electricity. Therefore, the ease with which these free electrons are available in a metal determines its conductivity.
In the case of gold, the outermost electron is located in the 6s subshell which is quite far from the nucleus due to which the impact of the binding force of the nucleus is minimal.
The first ionization energy of gold is 9.2257 eV. This means that these electrons get easily excited and jump away from their orbital even with the application of a small amount of energy.
Once they leave their orbit these electrons start moving aimlessly in free space around the atoms. However, in this state, they do not conduct electricity as the charges are canceled amongst themselves owing to unsystematic movement.
As soon as a voltage source is applied these electrons gain direction. As the electrons are negatively charged, hence they move away from the negative terminal of the source towards the positive terminal and thus, conduct electricity.
Electrical Conductivity of Gold
The electrical conductivity of a substance is the evaluation of its property of conduction i.e. how well does it perform as a conductor.
The unit of electrical conductivity is Siemens per meter (S/m) and is denoted by the symbol σ. Therefore,
Conductivity (σ) = Current Density/Electrical field strength
Here, current density and electric field strength are measured in ampere/meter square and volts per meter, respectively.
Also, as electrical conductivity is the reciprocal of electrical resistivity another formula is given as:
Conductivity (σ) = 1/Electrical Resistivity (ρ)
The value of electrical conductivity of gold is 4.10 X 107 which is very high.
The only substances that have electrical conductivity higher than gold are copper with an electrical conductivity value of 5.96 X 107, and silver with an electrical conductivity value of 6.30 X 107.
Therefore, the electrical conductivity of any two substances can be used to compare which of the two may serve as a better conductor.
The opposite of electrical conductivity is electrical resistivity which is the measure of complexity encountered by the charge carriers during the conduction of electricity in any particular substance.
In simple words, the higher the resistivity lower is the conductivity and vice versa.
In fact, the heating of a substance during the conduction of electricity is due to the resistance offered by that particular material. However, resistance is not always a bad thing, resistors are often used in the electrical circuits to protect them from damage by restricting the flow of current.
The electrical resistivity of gold is 2.44 X 10-8 which is very low again indicating that gold is a good conductor of electricity.
Why is Gold Used in Electronics?
By now we have learned that gold is a good conductor of electricity due to which it finds its role in a number of electrical equipment such as switch contacts, relay contacts, USB connectors, etc.
The properties of gold that makes it suitable for use in electronics are:
Easy Usage: Gold is more malleable and ductile than other metals. It is so soft and pliable that an approximately 80 km wire of Gold can be drawn out of one ounce of gold and also, 3 ounces of gold can be beaten into a sheet of about 28 square meters.
This makes gold very useful in the formation of thin wires used in various small electronics.
Tarnish Resistant: Being a noble metal, Gold is resistant to tarnishing i.e. it does not react with atmospheric oxygen. That means that wires made of Gold will have a longer life even in adverse conditions.
This is the reason you will often find Gold-plated materials in harsh environments, for example, lightning rods.
BTW, you should also go through an interesting article does white gold tarnish.
High Electrical conductivity: As discussed in the previous section, gold has high electrical conductivity and low electrical resistivity making it a good conductor of electricity.
Electrical Conductivity of Gold Vs. Copper
The electrical conductivity of copper is higher than gold. Also, copper is inexpensive and easily available metal due to which it is the first choice to be used in any type of electronics.
Gold, on the other hand, is a precious metal that is often related to royalty. It has traditionally been used in the making of jewelry as well as currencies of ancient times.
The question that arises here is that if copper is a better conductor and is also hustle-free available at a lower cost why is gold used in so many electronics.
The qualities of gold due to which it is favored over copper are its greater malleability and ductility, and the inert nature of gold. Copper is not that malleable and ductile in comparison to gold. Also, copper is susceptible to corrosion.
These properties of gold specially make it useful in more sophisticated electronics such as computers that have a maximum number of gold parts in them.
Moreover, some parts such as connectors need to be more robust and long-lasting due to which gold is used in their making instead of copper to enhance their efficiency and longevity.
You must also read out the article I wrote on why copper is a conductor.
Graph of Conductivity of Gold
The graph of conductivity of gold is drawn as a function of temperature i.e. what is the impact of temperature change on the conductivity of gold.
We already know that the conductivity of gold is due to the delocalized electrons present in free space around atoms.
Some amount of energy is required in the form of heat that increases the kinetic energy of the electrons due to which they get excited and instead of revolving around the nucleus they leave their orbit and come out into free space where they are available for conduction of electricity.
However, when more amount of heat is added to the system it further increases the kinetic energy of these electrons that start moving at higher speeds.
When an electric potential is applied to such a system the increased kinetic energy of these electrons works against the voltage due to which some electrons still keep moving randomly colliding with other electrons. This limits the flow of electricity and decreases the electrical conductivity.
Hence, the electrical conductivity of gold is inversely proportional to temperature and decreases as the temperature increases. This is true for all metals.
Below is the graph is given for the conductivity of gold and a few other metals as a function of temperature:
The above graph indicates that not just gold but the conductivity of all the metals decreases with a rise in temperature.
Gold conducts electricity owing to the presence of free electrons surrounding the atoms. These free electrons are actually the valence electrons that get excited by absorbing some amount of energy and moving out of their orbits.
The delocalized electrons normally move in random directions but as soon as an electric potential is applied they start moving from negative to the positive terminal, hence, conducting electricity.
The electrical conductivity is calculated using the formula
Conductivity (σ) = Current Density/Electrical filed strength
The electrical conductivity of gold is 4.10 X 107.
Gold is used in making a number of electronics as it is easy to use, tarnish-resistant, and has high electrical conductivity.
I hope you liked the article and if you want me to write an article on any specific topic, please feel free to suggest by your comment.
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