Which of the following is a good electrical conductor at 25 degrees C and one atmosphere? A) Fluorine, B) Phosphorus, C) Iodine, D) Aluminum, E) Silicon.
Good electrical conductivity is a property normally associated with metals. Electrical conductivity in metals is a result of the movement of electrically charged particles. In metallic structure, valence electrons, which are electrons from the outer shells of an atom, are free to move about. We use the word delocalized to describe these mobile electrons. If an external electric field or potential difference is applied to the metal, electrons move through the metallic lattice that forms the structure of the metal. The metal is conducting electricity.
At 25 degrees C and one atmosphere, which is normal room temperature and pressure, all metals are good electrical conductors. The metal atoms in the metallic lattice are not vibrating too much. And the electrons can pass by easily. At higher temperatures, we find the atoms vibrate more, making it harder for the electrons to pass through the lattice. The electrical conductivity of metals drops slightly at higher temperatures.
In this question, we’re looking for a good electrical conductor at normal temperatures. We can be sure that all metals are good electrical conductors under these conditions. Not all known metals share this property. In the periodic table, metals are located in the left-hand side and nonmetals on the right. We can easily locate the elements fluorine, symbol F, phosphorus, symbol P, iodine, symbol I, and silicon, symbol Si as nonmetals. Fluorine, phosphorus, and iodine all exist as simple molecules. There are no mobile electrons in these structures. They are not good conductors of electricity under normal conditions. Fluorine, phosphorous, and iodine are not correct answers.
Silicon is often referred to as a metalloid. In a crystal of silicon, there is an extensive network of covalent bonds between silicon atoms, similar to the structure in diamond. The valence electrons in silicon are mobile at higher temperatures. Silicon is described as a semiconductor. But it would not be described as a good electrical conductor at room temperature. Silicon is not the correct answer.
Aluminum is a metal and contains metallic bonding. There are mobile or delocalized electrons in its structure. And it is a good conductor of electricity at room temperature. It’s often used in electrical overhead transmission lines. Aluminum is the correct answer.