Physical Properties of metalloids. Metalloids comprises of boron,silicon,germanium,arsenic,antimony,tellurium,polonium and astatine. The metalloids, or semimetals, have properties that are somewhat of a cross between metals and nonmetals. Although chemical and physical differences can vary throughout the group. Arsenic and antimony are metalloids, bismuth is a metal. Chemically, they behave mostly as nonmetals. On the Periodic Table, there are three major types of elements known as Metals, Non-Metals, and Metalloids. Chemical Properties of Metalloids. Notice that aluminum borders the line, but it is considered to be a metal since all of its properties are like those of metals. They may display certain properties of metal or non-metals when reacting with certain chemicals. The physical properties of metalloids tend to be metallic, but their chemical properties tend to be non-metallic. The oxidation number of an element in this group can range from +5 to -2, depending on the group in which it is located. Metalloids, also known as semimetals are elements containing properties similar and midway between metals and nonmetals. What elements are metalloids? Examples of metals are Gold, Silver, Iron, Uranium, and Zinc. They are tricky to define because they have what is known as intermediate properties, meaning they can present properties that could belong to either the metals or nonmetals group. Metalloids tend to be economically important because of their unique conductivity properties (they only partially conduct electricity), which make them valuable in … Between the metals and nonmetals is a group of elements known as either the semimetals or the metalloids, which are elements that have properties intermediate between those of the metals and nonmetals.Most metalloids have a shiny, metallic appearance but are brittle, unexceptional electrical conductors and display nonmetallic chemical properties. Metalloids can also be called semimetals. The exception is hydrogen (H), the first element on the periodic table. They can form alloys with metals. Metals Metalloid Properties. The elements that are generally considered metalloids include boron, silicon, germanium, arsenic, antimony, and tellurium.