Carbon and Its Various Forms

The elemental composition of diamond is

[amp_mcq option1=”Carbon and Hydrogen” option2=”Carbon and Oxygen” option3=”Pure Carbon” option4=”Pure Silicon” correct=”option3″]

Diamond is an allotrope of carbon. This means it is a form of pure carbon where the carbon atoms are arranged in a specific crystal structure (a tetrahedral lattice). Therefore, diamond consists solely of carbon atoms and no other elements. Graphite is another well-known allotrope of pure carbon.

Allotropes are different structural modifications of an element. Diamond is a crystalline allotrope of carbon.

In diamond, each carbon atom is covalently bonded to four other carbon atoms in a rigid, three-dimensional tetrahedral network. This structure makes diamond extremely hard and gives it a high melting point.

Which among the following statements with respect to carbon is/are correct ?

• 1. Carbon forms the basis for all living organisms and many things we use
• 2. Carbon shows tetra-valency and the property of catenation
• 3. Carbon forms covalent bonds with itself and other elements
• 4. Carbon forms compounds containing triple and tetra bonds between carbon atoms

Select the correct answer using the code given below :

[amp_mcq option1=”1 only” option2=”1 and 2 only” option3=”1, 2 and 3″ option4=”2 and 4″ correct=”option3″]

Statements 1, 2, and 3 are correct. Carbon forms the backbone of all organic life and is present in countless materials we use (statement 1). Carbon has four valence electrons, allowing it to form four covalent bonds (tetra-valency), and it can bond with itself to form long chains or rings (catenation) (statement 2). Carbon forms covalent bonds not only with itself but also with other elements like hydrogen, oxygen, nitrogen, etc. (statement 3). Statement 4 is incorrect; carbon forms single, double, and triple bonds with other carbon atoms but not stable tetra (quadruple) bonds in typical organic chemistry contexts.

Carbon’s unique properties of tetra-valency and catenation, and its ability to form strong covalent bonds, are fundamental to organic chemistry and the diversity of carbon compounds. Carbon forms single, double, and triple bonds, but not quadruple bonds, between carbon atoms in stable molecules.

The vast number of carbon compounds makes organic chemistry a distinct branch of chemistry. Catenation is particularly strong in carbon, enabling the formation of complex molecular structures. While theoretical studies have explored the possibility of quadruple bonds in some exotic carbon species, they are not characteristic of carbon bonds in everyday substances.

Buckminster fullerene, which looks like a football, is an allotropic form of

[amp_mcq option1=”Phosphorus” option2=”Sulfur” option3=”Carbon” option4=”Tin” correct=”option3″]

Buckminster fullerene, which looks like a football, is an allotropic form of Carbon.

Allotropes are different structural modifications of an element. Carbon exists in several allotropic forms, including diamond, graphite, graphene, and fullerenes. Buckminster fullerene, also known as C60, is the most well-known fullerene molecule, consisting of 60 carbon atoms arranged in a spherical structure resembling a soccer ball (truncated icosahedron).

Fullerenes were discovered in 1985 by Robert Curl, Harold Kroto, and Richard Smalley, who were awarded the Nobel Prize in Chemistry in 1996 for their work. Other allotropes of carbon like diamond and graphite are well-known for their distinct physical properties arising from different atomic arrangements. Phosphorus, Sulfur, and Tin also have allotropes, but fullerenes are specific to Carbon.

Which one of the following statements is NOT correct ?

[amp_mcq option1=”Buckminsterfullerene is an allotrope of carbon” option2=”Diamond is a good conductor of electricity” option3=”Graphite is a good conductor of electricity” option4=”In graphite, each carbon atom is linked to three other carbon atoms” correct=”option2″]

The statement which is NOT correct is (B) Diamond is a good conductor of electricity. Diamond has a structure where each carbon atom is bonded to four other carbon atoms via strong covalent bonds. All valence electrons are tightly held in these bonds, meaning there are no free electrons to carry charge. Therefore, diamond is a poor conductor of electricity (a good electrical insulator).

Electrical conductivity in materials depends on the presence of free charge carriers, such as free electrons. The arrangement and bonding of atoms determine the availability of these carriers.

Statement (A) is correct: Buckminsterfullerene (C60) is a form of carbon, belonging to the fullerene family, which are allotropes of carbon. Statement (C) is correct: Graphite conducts electricity because each carbon atom is bonded to three others, leaving one delocalized electron per atom that can move throughout the layers. Statement (D) is correct: In graphite, carbon atoms are arranged in hexagonal layers where each carbon is covalently bonded to three other carbon atoms.