Final answer:
Representative elements are those where the last electron enters an s or p orbital, found in groups 1, 2, and 12-18 of the periodic table. Examples include metals like calcium and magnesium, as well as metalloids like silicon and germanium.
Step-by-step explanation:
Representative elements, also known as main-group elements, are elements in which the last electron added enters an s or p orbital. These elements are located in groups 1, 2, and 12-18 of the periodic table. Representative metals are those with metallic character within these groups, such as alkaline, alkaline earth, and certain p-block metals. Metallic character is demonstrated by the ability of an element to lose its outer valence electrons, leading to properties such as high thermal and electrical conductivity. Examples of representative metals include calcium (Ca), magnesium (Mg), and two metalloids that exhibit properties between metals and nonmetals, such as silicon (Si) and germanium (Ge), both of which are typically semiconductors. Other representative elements may include nonmetals like sulfur (S).