The metalloids or semimetals are elements with properties intermediate between the metals and nonmetals. As a group, metalloids have at least one shiny, metallic-looking allotrope. Solids are brittle, with nonmetal chemical properties. While metalloids are neither good electrical nor thermal conductors, they make excellent semiconductors and form amphoteric oxides. Take a closer look at the list of metalloids, their properties, and uses.
List of Metalloids
This is a list of the seven metalloid elements in order of increasing atomic number. Element 117 (tennessine) may also be a metalloid.
| NUMBER | SYMBOL | ELEMENT |
| 5 | B | Boron |
| 14 | Si | Silicon |
| 32 | Ge | Germanium |
| 33 | As | Arsenic |
| 51 | Sb | Antimony |
| 52 | Te | Tellurium |
| 84 | Po | Polonium |
| 117 | Ts | Tennessine |
Location of the Metalloids on the Periodic Table
The metalloids divide the periodic table along a zig-zag line between the metals on the left and the nonmetals on the right. Usually, the line runs under boron, germanium, antimony, and polonium. But, chemists disagree somewhat on metalloid classification. The line is more of a guide than a rule.
Metalloid Properties
Metalloids share the following properties:
- Metalloids are either dull or shiny.
- Most metalloids are solid at room temperature and pressure.
- These elements conduct heat and electricity, but not as well as the metals.
- Metalloids are good semiconductors.
- Most metalloids are malleable.
- Some metalloids are ductile.
- Atoms of metalloid elements both gain and lose electrons in reactions.
- Metalloids typically behave as nonmetals in chemical reactions.
- The have electronegativity values between those of metals and nonmetals.
- Their ionization energies are between those of metals and nonmetals.
- They form alloys with metals.
Metalloids display widely variable melting points, boiling points, and density values.
Metalloid Uses
The metalloids have many uses:
- Alloys
- Catalysts
- Flame retardants
- Semiconductors and electronics
- Glass
- Optical storage and optoelectronics
- Pyrotechnics
- Biological agents
References
- Brady, J.E.; Humiston, G.E.; Heikkinen, H. (1980). “Chemistry of the Representative Elements: Part II, The Metalloids and Nonmetals”. in General Chemistry: Principles and Structure (2nd ed.). John Wiley & Sons: New York. ISBN 0-471-06315-0.
- Chedd, G. (1969). Half-Way Elements: The Technology of Metalloids. Doubleday, New York.
- Goldsmith, R.H. (1982). “Metalloids”. Journal of Chemical Education. 59(6): 526–527. doi:10.1021/ed059p526
- Vernon, R.E. (2013). “Which Elements are Metalloids?”. Journal of Chemical Education. 90(12): 1703–1707. doi:10.1021/ed3008457