Potassium is a chemical element that lies in the first group of the periodic table. It is classified as an alkali metal. It is the seventh most abundant element present in the earth’s crust. It contributes 2.6 percent of the mass of planet earth.
Students may have many questions about Potassium’s electrical conductivity. It is a valid question to ask whether potassium can conduct electricity or not. In this article, I’ll discuss the electrical properties of Potassium.
So, does potassium conduct electricity? Yes, Potassium is a good conductor of electricity. It has a greater atomic radius as it has 4 shells and a single electron in its outermost shell. Therefore, it has smaller ionization energy and has relatively more free electrons due to which it is a good conductor of electricity.
Potassium is extracted from the igneous rocks, sediments in minerals. It exists as a white-silvery colored soft metal that can be easily cut with a knife.
Potassium is a reactive element, it readily reacts with oxygen on exposure to air and forms white-colored potassium peroxide. It is classified as an alkali metal that has only one electron in the outermost shell of its atom. This single electron can easily be removed to form positively charged ions (cation).
The Potassium in aqueous solution gets dissociated into potassium ions that are free to move in the solution and acts as a carrier to conduct the electricity on applying a potential difference across the solution.
2K + 2H2O ——-> 2KOH (potassium hydroxide) + H2 (hydrogen gas)
Potassium Hydroxide is a good conductor in aqueous solution. Potassium Hydroxide does not conduct electricity in solid-state. It can only conduct electricity in the molten state. As Potassium Hydroxide is an ionic compound, therefore, the free ions in a liquid state can easily flow and conduct the electricity.
It should be noted that the basic requirement for any substance to conduct electricity is the flow of electrons. Free electrons are the carriers of electric current. If a substance lacks delocalized or free electrons, It does not flow the electrons across it that makes it an insulator or poor conductor of electricity.
On the other hand, Potassium is rich in free electrons which can allow the transport of mobile electrons that conducts the electricity.
Potassium has its greater atomic radius as it contains 4 electronic shells. And only 1 electron is present in the outermost shell. Therefore, it takes a lesser amount of energy to remove the valence electron. The ionization energy of potassium is 419 kJ/mol.
Ionization energy is defined as the minimum energy required for removing the valence electron out of the atom.
The heat conductivity of potassium is also good because of the presence of free electrons. The free electrons also contribute to the conductivity of heat. The thermal conductance is produced by the vibrations of free electrons.
Electrolysis of Potassium Chloride (KCl)
In high schools, the experiment of electrolysis of salts is done to show the flow of conductivity in the form of ions. There are many varieties of salts preferred in the case of electrolysis. Some of the examples of such salts are Sodium Chloride (NaCl), Potassium Chloride (KCl), etc.
The conductivity of potassium can be understood with the explanation of the electrolysis of Potassium Chloride.
Here are the steps for electrolysis:
- Take a beaker containing the aqueous solution mixed with potassium chloride (KCl).
- Fix the two electrodes (positively charged and negatively charged) at two ends of the beaker containing the solution.
- A potential difference is applied across the solution. The positively charged electrode is known as anode and the negatively charged electrode is known as the cathode.
- When the voltage is applied across the solution, the (potassium ion) K+ ions start moving towards the cathode and chloride ions (Cl-) start moving towards the anode that in return creates an electric field.
The free electrons moving from the negative terminal to the positive terminal generates the electric current.
Factors that affect the conductivity of an electrolyte
Type of electrolyte: A strong electrolyte is an electrolyte that completely ionizes in the solution. In such electrolyte large number of ions are present whereas weak electrolyte contains a few numbers of ions.
Some of the examples of strong electrolytes are Sodium Chloride, Potassium Hydroxide, and Sodium Hydroxide.
The strong electrolytic solution contains a greater number of ions and therefore, has more conductance of electricity because the number of free ions is only responsible for the flow of current.
And the weak electrolyte dissociates to a small extent due to which it gives few ions. Therefore, the weak electrolyte has a lower conductance of electricity.
Concentration: The electrical conductivity of an electrolytic solution varies with its concentration. The molar conductance of an electrolyte increases with a decrease in concentration.
The variation in conductance on decreasing concentration of the electrolyte is different for strong and weak electrolytes.
Concentration effect on strong electrolyte: On increasing the dilution of strong electrolyte, the number of ions do not increase because the strong electrolyte is already dissociated almost completely.
But in a concentrated strong electrolyte, there exist inter-ionic forces of attraction among the ions. Therefore, due to these inter-ionic forces of attraction, the flow of ions becomes difficult that decreases the conductivity of electricity.
On dilution, these inter-ionic forces of attraction become weak and ions get far from each other and due to which the molar conductivity of electricity increases.
Concentration effect on weak electrolyte: The number of ions present in an electrolytic solution depends upon the extent of dissociation it undergoes.
On dilution, the degree of dissociation increases. As a result of the number of ions increases that flow electric current and therefore, molar conductivity also increases.
Temperature: With the increases in temperature, the degree of dissociation also increases. Therefore, the number of ions increases to flow across the solution that increases the conductivity of electricity.
Physical properties of Potassium
- Potassium is a porous, soft element.
- It has a white-silvery color.
- The melting point of potassium is around 63 degrees Celcius(145 degrees Fahrenheit).
- The boiling point of potassium is around 770 degrees Celcius(1420 degrees Fahrenheit).
- The density of this element is calculated around 0.862 grams per cubic centimeter.
- Potassium can float on the water because the density of water (1.00 grams per cubic centimeter) is greater than the density of potassium.
Chemical properties of Potassium
- Potassium is a very reactive metal as like other alkali metals.
- It readily reacts with water and liberates hydrogen gas and this reaction creates a high amount of heat that hydrogen gas can also catch fire.
- It can also react vigorously with all non-metals.
- The atomic mass of potassium is around 39.0983 u.
- The atom of this element contains 19 electrons and protons each and 20 neutrons.
- Its atom contains four energy levels.
- The crystal structure of potassium is a body-centered cubic (bcc).