Question

Identify two nonmetallic elements that have allotropes and describe the allotropes of each.

Short answer

Carbon (diamond, graphite) and oxygen (dioxygen, ozone) have allotropes.

Step-by-step solution

Understanding Allotropes

Allotropes are different structural forms of the same element in the same physical state. They have different physical properties and sometimes different chemical properties due to differences in their molecular structures.

Identifying Nonmetallic Elements with Allotropes

Nonmetallic elements that are known to have allotropes include carbon and oxygen. These elements can exist in multiple distinct forms, each with unique properties.

Describing Carbon Allotropes

Carbon is a well-known nonmetallic element that has several allotropes including diamond, graphite, and graphene. Diamond is a high-hardness form with a tetrahedral structure, graphite consists of layers of hexagonally-arranged carbon atoms, and graphene is a single layer of graphite with unique electrical properties.

Describing Oxygen Allotropes

Oxygen has two important allotropes: dioxygen ( O_2 ) and ozone ( O_3 ). Dioxygen is the form we breathe and use for combustion. Ozone has a distinct trioxide composition and is known for its protective layer in the Earth's stratosphere.

Key concepts

Nonmetallic Elements

Nonmetallic elements are a diverse group of elements characterized by their lack of metallic properties. Unlike metals, they are poor conductors of electricity and heat, and they often have lower melting and boiling points.
These elements are more likely to gain electrons in chemical reactions, forming anions or sharing electrons through covalent bonds.
Some of the most common nonmetallic elements include:

• Carbon (C)
• Oxygen (O)
• Nitrogen (N)
• Sulfur (S)
• Phosphorus (P)

Numerous nonmetallic elements possess allotropes, which are distinct forms of the same element differing in molecular arrangement. This unique ability to form allotropes allows nonmetals to exhibit varied physical and chemical properties.
Particularly, carbon and oxygen have fascinating allotropes that showcase the versatility and adaptability of nonmetallic elements.

Carbon Allotropes

Carbon is a remarkable nonmetallic element known for its ability to form a variety of allotropes, each with distinctive properties. The allotropes of carbon largely differ in their arrangement of carbon atoms, which results in differing characteristics.
Some of the most well-known carbon allotropes include:

• Diamond: In diamond, carbon atoms are arranged in a tetrahedral lattice, which is extremely strong, making diamond the hardest known natural material. This structure lacks electrical conductivity but boasts impressive optical properties.
• Graphite: In graphite, carbon atoms form sheets of hexagonally arranged atoms. These layers can slide over each other, giving graphite a slippery feel and making it an excellent lubricant and conductor of electricity.
• Graphene: A single layer of graphite, graphene, is celebrated for its exceptional electrical conductivity and strength, despite being one atom thick. Graphene's attributes have implications for developing advanced technological applications.

The ability of carbon to form these diverse allotropes is a testament to its versatility and crucial role in various scientific and industrial fields.

Oxygen Allotropes

Oxygen is another nonmetallic element with notable allotropes, each playing essential roles in different environmental and chemical processes. The structural differences between these allotropes can profoundly affect their chemical behavior and applications.
Major oxygen allotropes include:

• Dioxygen (\(O_2\)): This is the most common form of oxygen, vital for life as it is involved in respiration and combustion. Usually, it exists as a colorless, odorless gas, constituting about 21% of Earth's atmosphere.
• Ozone (\(O_3\)): Ozone differs from dioxygen by having three oxygen atoms. It forms a protective layer high in Earth's atmosphere, absorbing the majority of the sun's harmful ultraviolet radiation. Ozone at ground level, however, is a pollutant that can harm human health and vegetation.

Understanding oxygen's allotropes is crucial, as they have significant implications for environmental science and pollution control. Each form serves an irreplaceable role in both biological systems and atmospheric processes.