The elements are broadly sorted into three major categories: metals, nonmetals, and metalloids. Metals are typically known for their strength and shine, while nonmetals are often gases or brittle solids. Metalloids act as transitional elements, exhibiting a fascinating blend of traits inherited from both sides. This article focuses on the primary nonmetallic properties that metalloids share, most notably their limited ability to conduct energy.
Categorizing Elements on the Periodic Table
The organization of the periodic table visually represents the separation of element properties. A distinctive “staircase” line, running from Boron down to Astatine, acts as the boundary between the two major groups. Elements to the left are classified as metals, which are mostly solids at room temperature and have high melting points. Nonmetals are primarily located on the right side, often existing as gases or volatile liquids. Metalloids are the small group of elements that border this dividing line.
The Shared Property of Poor Conduction
The most significant property metalloids share with nonmetals is their reduced ability to conduct heat and electricity compared to metals. Metals are excellent conductors because their valence electrons are delocalized, forming a “sea of electrons” that efficiently carries energy. Nonmetals, conversely, are typically insulators because their valence electrons are tightly bound to individual atoms, restricting current flow.
Metalloids, which are also known as semiconductors, occupy a middle ground in electrical conductivity. They are much poorer conductors than metals, behaving more like nonmetals at lower temperatures. Their unique atomic structure allows their conductivity to be manipulated, unlike true nonmetals. By adjusting factors like temperature or introducing specific impurities through doping, the conductivity of a metalloid like silicon can be significantly increased.
Other Nonmetallic Physical Traits
Beyond electrical properties, metalloids exhibit several physical and chemical traits that align them with nonmetals. A notable shared physical characteristic is their brittleness in the solid state. Unlike metals, which are generally malleable and ductile, metalloids shatter easily when subjected to stress. This trait is also common among solid nonmetals, such as sulfur or phosphorus.
Furthermore, the chemical behavior of metalloids often resembles that of nonmetals, particularly in how they bond. Nonmetals tend to gain or share electrons when forming compounds. Metalloids similarly favor forming chemical bonds by sharing electrons, known as covalent bonding, especially when reacting with nonmetals. This is in contrast to metals, which predominantly lose electrons to form positive ions in chemical reactions.