Question

All the Group \(1 \mathrm{A}\) (1) and \(2 \mathrm{A}\) ( 2 ) metals are produced by electrolysis of molten salts. Why?

Short answer

Group 1A and 2A metals are produced by electrolysis of molten salts because of their electropositive nature and low ionization energies, which cause them to readily form ionic compounds like salts with non-metals. Electrolysis is an efficient method to break the bonds between ions, as it allows for the chemical decomposition of the compound. In molten salts, the ions are free to move, making the process more effective and bypassing potential side reactions with oxygen.

Step-by-step solution

Understand the properties of Group 1A and 2A metals

Group 1A and 2A metals are also known as alkali and alkaline earth metals, respectively. These metals tend to lose electrons easily, forming positive ions. They are highly electropositive and have low ionization energies. This property allows them to readily form ionic compounds by reacting with non-metals, such as halogens.

Understanding the concept of electrolysis

Electrolysis is a process that uses an electric current to induce a chemical change, leading to the decomposition of a compound. When a molten ionic compound is subjected to an electric current, the ions in the compound are free to move, allowing them to travel to the electrodes. At the anode (positive electrode), negative ions lose electrons and become non-metal atoms. At the cathode (negative electrode), positive ions gain electrons and become metal atoms.

Explain why Group 1A and 2A metals are produced by electrolysis of molten salts

As mentioned earlier, Group 1A and 2A metals, due to their electropositive nature and low ionization energies, readily react with non-metals to form ionic compounds like salts. To extract these metals from their ionic compounds, the bonds between the ions need to be broken. Electrolysis proves to be an efficient method for achieving this task, as it allows for the chemical decomposition of the compound, with the ions moving towards the respective electrodes. In the case of molten salts, the ions are free to move, making the process more effective. Moreover, the process bypasses any potential side reactions that could involve oxygen, which would be present in the extraction of metals from their ores through standard reduction methods. Hence, Group 1A and 2A metals are produced through electrolysis of molten salts.

Key concepts

Group 1A and 2A Metals

Group 1A and 2A metals encompass the elements commonly known as alkali metals and alkaline earth metals, respectively. These metals, including lithium, sodium, and potassium from Group 1A, and magnesium and calcium from Group 2A, are characterized by their shiny appearance and soft texture.

They have distinctive properties that set them apart from other elements on the periodic table. One of the most notable is their reactivity, especially with water, which can be dramatically exothermic. The metals from these groups often occur in nature as part of compounds, rather than in their pure elemental form, due to their high reactivity.

Electropositive Nature

The term electropositive refers to an element's tendency to donate electrons and form positive ions, known as cations. Group 1A and 2A metals are highly electropositive because they have only one or two electrons in their outermost shell, which they can lose easily.

This loss of electrons results in a cation with a stable electronic configuration, which is energetically favorable for these metals. The creation of these cations is fundamental to the metals' involvement in various reactions, including their dissolution in water and the formation of ionic compounds like salts.

Ionization Energies

Ionization energy is the amount of energy required to remove an electron from an atom or ion in its gaseous state. Group 1A and 2A elements have relatively low ionization energies compared to other elements, meaning it takes less energy to remove their valence electrons.

As you move down the groups on the periodic table, the ionization energy tends to decrease because the outer electrons are farther from the nucleus and less tightly held. This trend contributes to the metals' electropositive nature and affects the way these elements react chemically.

Ionic Compounds

Ionic compounds are formed when atoms of metals react with nonmetals to form ionic bonds. In these reactions, metals donate electrons to nonmetals, resulting in a compound composed of positively charged metal cations and negatively charged nonmetal anions.

For example, when sodium, a Group 1A metal, reacts with chlorine, it donates its valence electron to chlorine, forming sodium chloride (NaCl), a stable ionic compound composed of Na+ and Cl- ions. The robust electrostatic attraction between oppositely charged ions is the driving force behind the formation of these compounds. The process of electrolysis takes advantage of this ionic nature to facilitate the extraction of metals through the separation of ions in molten salts.