Metalloids, also known as semimetals, are a unique category of elements that possess properties of both metals and non-metals. These elements often share characteristics with metals, making them crucial in various scientific and industrial applications.
This article will explore the definition of metalloids or semimetals, list the elements that fall under this category, and discuss their properties, uses, and significance.
Here are the findings to help you better understand these versatile elements.
What Are Metalloids Or Semimetals?
Metalloids are chemical elements that display a mixture of metallic and non-metallic properties. They are typically semiconductors, which means they can conduct electricity, but not as efficiently as metals. The characteristics of metalloids make them useful in various applications, particularly in electronics and other fields that require semiconductive materials.
Metalloids are typically found along the “staircase” line on the periodic table, which separates metals from non-metals. This staircase starts at boron (B) and stretches to astatine (At). While the exact properties can vary from one metalloid to another, most share key features like their ability to act as semiconductors and relatively high melting points compared to non-metals.
List Of Metalloids Or Semimetals
Several elements are classified as metalloids. These elements lie on the periodic table’s boundary between metals and non-metals. Here is a list of common metalloids:
- Boron (B)
- Silicon (Si)
- Germanium (Ge)
- Arsenic (As)
- Antimony (Sb)
- Tellurium (Te)
- Polonium (Po)
These elements exhibit varying degrees of metallic and non-metallic characteristics. The most common of these is silicon, which is widely used in the electronics industry to produce semiconductors.
Properties Of Metalloids
Metalloids possess a range of properties that distinguish them from metals and non-metals. Below are some key properties that are common among metalloids.
Physical Properties
- Appearance: Metalloids typically have a metallic lustre, which means they shine when polished. However, they are brittle and not malleable like metals.
- Conductivity: One of the most significant properties of metalloids is their electrical conductivity. Metalloids can conduct electricity, but not as much as metals. This makes them ideal for semiconductors, where the conductivity can be controlled.
- Melting and Boiling Points: Metalloids generally have higher melting and boiling points than non-metals but lower than metals. For instance, silicon has a melting point of 1414°C, considerably higher than most non-metals.
- Density: Metalloids are denser than non-metals, although their density is not as high as that of metals. For example, germanium has a density of 5.323 g/cm³, which is higher than many non-metals but lower than most metals.
Chemical Properties
- Reactivity: Metalloids exhibit chemical properties that are intermediate between metals and non-metals. Depending on the elements they react with, they can form ionic and covalent bonds.
- Acidity: Some metalloids, like arsenic and antimony, can form acidic oxides when they combine with oxygen. These oxides are similar to those of non-metals.
- Electronegativity: Metalloids tend to have intermediate electronegativity values between metals and non-metals. For example, silicon has an electronegativity of 1.90, between metals like sodium and non-metals like oxygen.
Semiconductor Properties
A defining feature of metalloids is their semiconductor nature. Semiconductors are materials that can conduct electricity under certain conditions but not others. This property makes metalloids essential for modern technology, particularly in creating electronic components such as transistors, diodes, and solar cells.
Examples Of Semiconductors
- Silicon (Si): Silicon is the electronics industry’s most widely used semiconductor material. It is primarily used in computer chips, solar cells, and other electronic devices.
- Germanium (Ge): Germanium was historically used in early transistors before silicon became the dominant material in electronics. It is still used in specific applications like infrared optics.
Uses Of Metalloids
Metalloids are used in various applications, especially in electronics and technology. Below are some notable uses of metalloids:
Silicon In Electronics
Silicon is the backbone of modern electronics. It is used in the production of:
- Transistors are the fundamental building blocks of modern electronic devices such as computers and smartphones. Silicon-based transistors can switch on and off, enabling the control of electrical current.
- Solar Cells: Silicon is also used in photovoltaic cells, which convert sunlight into electricity. These cells are a key component in renewable energy technologies.
- Microchips: Microprocessors, memory chips, and other types of integrated circuits are commonly made from silicon.
Other Uses Of Metalloids
- Boron: Boron is used to manufacture glass, ceramics, and detergents. It is also used in nuclear reactors as a neutron absorber.
- Germanium: Germanium is used in fibre optic cables, infrared optics, and semiconductor devices.
- Arsenic: Arsenic compounds are used to produce pesticides and wood preservatives. They are also used in electronics and solar cells.
- Antimony: Antimony is used in flame retardants, alloys, and lead-acid batteries.
- Tellurium: Tellurium is used to manufacture solar panels, thermoelectric devices, and alloys.
- Polonium: Polonium is used in specific atomic devices and as a heat source for space missions.
Metalloids Vs. Metals And Non-Metals
Metalloids, metals, and non-metals all have distinct characteristics, but metalloids occupy a unique position on the periodic table, showing traits of both. Below is a comparison of metalloids with metals and non-metals.
Metals
- Conductivity: Metals are excellent conductors of electricity, while metalloids have moderate conductivity.
- Malleability: Metals are malleable and can be hammered into thin sheets. Metalloids, however, are brittle and break easily.
- Lustre: Metals have a shiny appearance, while non-metals tend to be dull. Metalloids usually have a metallic lustre, but not as shiny as metals.
Non-metals
- Conductivity: Non-metals are generally poor conductors of electricity. In contrast, metalloids can conduct electricity, although not as much as metals.
- Malleability: Non-metals are typically brittle and cannot be shaped like metals. Metalloids are also brittle, but they are more flexible in their physical properties compared to non-metals.
- Reactivity: Non-metals are often more reactive than metalloids. For example, non-metals like oxygen and fluorine are highly reactive, while metalloids like silicon and boron are less reactive.
Conclusion
Metalloids, or semimetals, exhibit metallic and non-metallic properties, making them valuable in various applications, particularly electronics. These elements, including boron, silicon, germanium, arsenic, antimony, tellurium, and polonium, are primarily semiconductors, allowing controlled electrical conductivity. They possess a metallic lustre, intermediate conductivity, and higher melting points than non-metals.
Chemically, metalloids can form both ionic and covalent bonds and have electronegativity values between metals and non-metals. Their versatility in industries like technology, energy, and manufacturing highlights their critical role in modern science, especially in producing transistors, solar cells, and microchips.
Frequently Asked Questions
What Makes Metalloids Different From Metals And Non-Metals?
Metalloids possess properties that lie between metals and non-metals. Unlike metals, which are good conductors of electricity and malleable, metalloids have moderate conductivity and are brittle. Compared to non-metals, which are poor conductors and dull, metalloids often have a metallic lustre and can conduct electricity to some extent, making them essential for semiconductor applications.
What Are Some Common Uses Of Metalloids In Technology?
Due to their semiconductor properties, metalloids, primarily silicon and germanium, are crucial in the electronics industry. They are used to produce components like transistors, microchips, and solar cells. Silicon, in particular, is the backbone of modern electronics, found in everything from computers to smartphones and solar panels.
Why Are Metalloids Considered Semiconductors?
Metalloids are semiconductors because they have electrical conductivity properties that can be controlled under certain conditions. Unlike metals, which always conduct electricity efficiently, metalloids can act as insulators or conductors depending on temperature, light exposure, or doping with other elements. This makes them ideal for use in electronic devices like transistors and diodes.