Is Silicon a Metal or Nonmetal? (+ 3 Things You Should Know)

Silicon is neither a metal nor a nonmetal. Silicon is a metalloid, an element that has properties of both metals and nonmetals. ¹ Silicon is a hard, brittle crystalline solid with a blue-grey metallic lustre. It is a tetravalent metalloid and semiconductor. ²

Well, this was just a simple answer. But there are few more things to know about this topic which will make your concept super clear.

So let’s dive right into it.

Why is silicon a metalloid?

Silicon is classified as a metalloid because it has properties of both metals and nonmetals. Metalloids, also known as semimetals, are elements that have characteristics of both metals and nonmetals. 

Like metals, silicon is a solid at room temperature, has a metallic luster, and is a good conductor of electricity. ³

However, it is not a good conductor of heat and is brittle, like nonmetals. 

Additionally, silicon has a relatively high melting point and is not malleable or ductile like metals. ⁴

Silicon also has an intermediate electronegativity, which is a measure of an element’s ability to attract electrons. ⁵

This property is similar to nonmetals, which typically have higher electronegativities than metals.

Overall, silicon’s properties place it between those of metals and nonmetals, making it a metalloid or semimetal.

Properties of silicon that classify it as a metalloid

Here are some properties of silicon that classify it as a metalloid:

• Intermediate conductivity: Silicon is a semiconductor, which means that it has intermediate electrical conductivity between that of a metal and an insulator. This is because it has a partially filled valence band and an empty conduction band. Metals have high electrical conductivity, while nonmetals have low electrical conductivity. ⁶
• Brittle: Silicon is brittle and breaks easily, like nonmetals. This is because its atomic structure consists of a network of covalent bonds, which makes it rigid and inflexible. ⁷ In contrast, metals are malleable and ductile, meaning they can be shaped and bent without breaking.
• High melting point: Silicon has a relatively high melting point, similar to metals. This is because its covalent network structure requires a large amount of energy to break apart. Nonmetals have lower melting points than metals and metalloids.
• Semiconductor behavior: Silicon can be used as a semiconductor in electronic devices, which is a property of metalloids. Semiconductors have a range of electrical conductivity that can be controlled by adding impurities, making them useful in the electronics industry. ⁸
• Intermediate electronegativity: Silicon has an intermediate electronegativity, similar to nonmetals. Electronegativity is the measure of an element’s ability to attract electrons. Metals have low electronegativity, while nonmetals have high electronegativity. ⁹

In summary, silicon’s properties place it between those of metals and nonmetals. Its intermediate conductivity, brittleness, high melting point, semiconductor behavior, and intermediate electronegativity are characteristics of both metals and nonmetals.

How is silicon different from other metalloids?

Silicon is one of the most well-known and widely used metalloids, but it is different from other metalloids in several ways. 

Here are some ways in which silicon differs from other metalloids:

• Abundance: Silicon is the second most abundant element in the Earth’s crust, making up about 28% of its mass. This abundance is much greater than other metalloids such as boron, which is much less common. ^{10 11 12}
• Properties: Silicon’s properties make it highly useful in electronics and other industries. For example, its semiconductor behavior makes it a key component in computer chips and solar panels. In contrast, other metalloids like arsenic and antimony are toxic and have limited industrial uses. ¹³
• Biological role: Silicon is an essential nutrient for many living organisms, including humans. It plays a role in the growth and development of bones, cartilage, and connective tissue. Other metalloids like boron and arsenic have no known biological role or are toxic to living organisms. ¹⁴
• Allotropes: Silicon has several allotropes, or different forms of the same element with different structures and properties. These include amorphous silicon, which is used in solar panels, and crystalline silicon, which is used in computer chips. ¹⁵ Other metalloids like boron and arsenic have only one allotrope.

Overall, while silicon shares some properties with other metalloids, it also has unique characteristics that set it apart. Its abundance, properties, biological role, reactivity, and allotropes distinguish it from other metalloids and make it a highly versatile and important element in many industries.

Further reading

Is Phosphorus a Metal or Nonmetal?
Why is Sulfur a Nonmetal?
Is Chlorine a Metal or a Nonmetal?
Is Argon a Metal or Nonmetal?
Is Potassium a Metal or Nonmetal? 

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