Q. What are Metalloids?
Answer: Metalloids are chemical elements that have properties of both metals and nonmetals. There are 25 metalloids in the periodic table, with the most common being bismuth, antimony, tellurium, polonium, and germanium.
They all have a metallic luster; like metals, however, they react to other substances much differently than metals do. For example, a typical metal will melt at about 3000 degrees centigrade, but some metalloids can not be melted until at least 1000 degrees centigrade. Metals are usually strong and rigid, but metalloids are brittle and soft. Some metals are good conductors of heat and electricity, but some metalloids do not conduct electricity very well. Some metals will generally react violently with other substances, while most metalloids react with few exceptions to producing only weak products.
Properties of Metalloids:
- All metalloids are insoluble in water and acids.
- They are nearly always ductile and malleable, but some are brittle.
- Their melting points may be as low as 400 C or as high as 1500 C.
- The electrical conductivity of most metalloids is very low compared to metals; for example, in the case of tellurium, only 5% of the conductivity value obtained for copper is obtained for tellurium.
- Their density is close to that of water at room temperature (for example, bismuth is only 2.6 times heavier than water).
- Some metalloids react more violently with some solutions, such as acids and alkalis, than metals. The reason for this is that the formation of a compound may involve the breaking up of an existing compound.