Valence electrons are the outermost electrons of an atom and play a crucial role in chemical bonding. These electrons determine how an atom interacts with others, influencing its reactivity and the types of bonds it can form. For example, elements in the same group of the periodic table, like the noble gases or alkali metals, have similar numbers of valence electrons, which leads to similar chemical properties. Understanding valence electrons helps explain why certain elements, such as sodium and chlorine, combine to form compounds like sodium chloride (table salt). The transfer or sharing of valence electrons between atoms allows them to achieve a more stable electron configuration, often resembling that of the nearest noble gas.