Which group of elements is characterized by being good conductors and having a tendency to lose electrons in a reaction?

The group of elements characterized by being good conductors of electricity and having a tendency to lose electrons in a reaction is indeed metals. Metals are typically solid at room temperature (with the exception of mercury) and exhibit properties such as luster, malleability, ductility, and good electrical and thermal conductivity.

In chemical reactions, metals tend to lose electrons to form positive ions, a property that is fundamental to many chemical processes, including reactions with nonmetals. For example, when metals react with nonmetals, they often transfer their outermost electrons to achieve a stable electron configuration, usually corresponding to the nearest noble gas. This ability to easily lose electrons is what distinguishes metals from nonmetals, which generally gain or share electrons, and metalloids, which have intermediate properties. Noble gases, on the other hand, are known for their stability and lack of reactivity due to having full valence electron shells.

Thus, the properties of metals make them highly conductive and likely to participate in electron-losing reactions, making them the correct answer to this question.