In a chemical cell, the anode and cathode are determined by the metal’s tendency to ionize, a process that generates energy through the movement of electrons and the flow of electric current. Metals with a greater tendency to ionize are more likely to become cations, which has a significant impact on the performance and efficiency of the cell.
A chemical cell is a device that generates electricity through a chemical reaction, and the batteries we use every day are a type of chemical cell. They come in a variety of sizes and shapes, and are widely used in a variety of applications, including household, industrial, and medical. These batteries contain specific chemicals inside, which generate an electric current. Chemical batteries use several different materials and electrolytes to provide electricity, and these components greatly affect the performance and lifespan of the battery. When using batteries, it’s important to match the anode and cathode correctly. This is directly related to the efficiency and safety of the cell, and an incorrect connection can cause the cell to not function properly or even be damaged. This is because the electrodes of a chemical cell are the anode, where reduction occurs to gain electrons, and the cathode, where oxidation occurs to lose electrons, and electrons move from the cathode to the anode.
The anode and cathode of a chemical cell are determined by the ionization tendency of the metals that make up the electrodes. The ionization tendency is the degree to which a metal is prone to losing electrons in solution and becoming a cation. This is an important factor in the performance of a cell, greatly affecting its efficiency and lifespan. Therefore, metals with a high ionization tendency dissolve easily in electrolyte solutions and become cations. A chemical cell is made by placing copper and zinc plates as electrodes in a dilute aqueous solution of sulfuric acid (H2SO4). Because zinc has a greater tendency to ionize than copper, the zinc atoms on the surface of the zinc plate become positive ions, and the electrons that leave the zinc atoms move along the wire to the copper plate. Current flows in the opposite direction of electrons, so the copper plate is the positive electrode and the zinc plate is the negative electrode. If you replace the zinc plate with a silver plate, replace the sulfuric acid solution with an aqueous solution of sodium chloride, and connect the copper and silver plates with a wire, the copper plate becomes the cathode and the silver plate becomes the anode. This is because copper has a greater tendency to ionize than silver. In a chemical cell, the anode and cathode are determined by the relative magnitudes of the ionization tendencies of the two metals.
Chemical cells are not just a means of storing energy, but are also seen as an important key to efficiently utilizing renewable energy and solving future energy problems. For example, large chemical cells can be used to store electricity generated from renewable energy sources such as solar energy or wind energy. Unlike the small batteries we use every day, these cells have the ability to store and deliver energy on a large scale.
The tendency of a metal to ionize can be compared to the magnitude of the heat of reaction. To understand this, we need to know the process by which a single atom breaks away from the metal and becomes a hydrated ion. In general, metals have a crystalline structure with many metal atoms bonded together. Metals primarily lose electrons to become cations, and a single metal atom must break away from the crystal to become an individual ion. For example, when one atom of zinc metal (Zn) in an electrolyte solution breaks away, it loses two electrons and becomes a zinc ion (Zn2+). This reaction requires energy, so the zinc metal absorbs heat. When this chemical reaction takes place, it is called an endothermic reaction. The zinc ions are then hydrated in an electrolyte solution. This reaction releases energy, which is called an exothermic reaction.
In the ionization tendency of metals, the heat of reaction is determined as the amount of heat absorbed or released when a chemical reaction occurs at a constant temperature. Therefore, when comparing the ionization tendency with the heat of reaction, the heat of the endothermic reaction and the heat of the exothermic reaction are combined. Reaction heats are labeled with a sign, usually positive for exothermic reactions and negative for endothermic reactions. Since the magnitude of the ionization tendency increases with the value of the reaction heat, it can be seen that the magnitude of the ionization tendency is related to the magnitude of the heat in the exothermic reaction and the magnitude of the heat in the endothermic reaction. The list of metal elements based on the magnitude of their ionization tendency is called the ionization sequence. The ionization sequence makes it easy to know which metals will be the anode and which will be the cathode in a chemical cell. This is an important criterion in the design and fabrication of cells, and the choice of metals based on their ionization sequence greatly determines the performance and efficiency of the cell.
