Anomalous Behaviour of Carbon

Anomalous behavior is a behavior that is different from its original order. It shows different properties from other members of its groups. Elements that show anomalous behavior have unique properties and form different compounds. We know that carbon is found in the earth's atmosphere in various free and combined states in the form of organic compounds. Carbon is present in the form of carbonates, coal, hydrogen carbonates, carbon oxides such as Carbon-di-oxide, Carbon monoxide etc. Carbon is essential for our existence and it is used for various purposes. Carbon is an element of group-14, and it belongs to p-block according to the modern periodic classification of elements. Carbon is a non-metal which is present in the 14th group in the first place.    

Anomalous Behavior of Carbon

Earth's crust contains 0.02% of carbon in different states. Carbon is the first element of the group which shows different properties from other members of the group. Carbon shows anomalous behavior due to various properties as exceptional size, high electrification, high ionization energy, and absence of d-orbitals. Carbon has high melting and boiling point compared to the other elements of the same group.

As we move down the group, the tendency of melting and boiling points decreases.

Some other important properties of carbon are:

•    Tetravalency of a carbon atom

•    Catenation

•    Small size of an atom

•    Electronegativity

Tetravalency Of Carbon

Tetravalency (tetra means four) is the property of an element to form a covalent bond by sharing four electrons with other elements. Carbon is the element that has four electrons within its outermost shell or it can be said that carbon requires four electrons to complete its outermost shell. Its electronic configuration lies in the s and p shell. 

The property of the carbon atom of forming a covalent bond by sharing its outermost four electrons with other elements is known as the tetravalency of carbon atom. 

Electronic configuration : 1s2, 2s2, 2p2

The valence of carbon is four which means it has tetravalency (four valencies) and can form bonds with four elements.

For Example

CH4 (methane) is an organic compound formed with the sharing of electrons between one carbon atom and four hydrogen atoms. Here carbon shares its four electrons one each with each hydrogen atom to form four covalent bonds. 

Catenation

Catenation is a property of an element that can form a long chain compound by combining it with its element itself. Catenation is a property that is shown by carbon atoms due to which it can form a long chain compound with other carbon atoms. A compound formed can be straight, branched, and ring-shaped compounds.

The small size of the carbon atom helps in the purpose of forming multiple bonds and is also responsible for building the property of catenation. Carbon is a half-filled element with four electrons in its outermost elements due to which it is stable as the nucleus can hold the bonded and non-bonded electrons.

Catenation property mainly depends upon the bond energy of elements. The bond energy of the carbon-carbon covalent bond is high due to which it can form a long chain compound.

Due to the catenation property of carbon atoms it has the capacity to maintain four different allotropes known as graphite, diamond, Buckminsterfullerene, and lead.

NOTE: Diamond is one of the allotropes of carbon and is the hardest metal of the group.

As we go down the group the bond energy between elements decreases from Si to Pb.

C > Si > Ge = Sn >> Pb

For Example

C6H12, C9H9 are some organic compounds formed by the sharing of electrons between carbon and hydrogen atoms and forms a long chain compound.

Electronegativity

Electronegativity is the property of an atom to attract a shared number of electrons in a covalent bond. Carbon forms pp-pp multiple bonds with itself and other molecules due to high electronegativity and small size of a carbon atom.

Whereas other elements of the same group do not form pp-pp multiple bonds due to large atomic orbital and the presence of d-orbital in other elements that form deep bonds. The tendency of d-p bond formation is also decreased down the group as we move down the group.

FAQ (Frequently Asked Questions)

1. What is the Benefit of the Catenation Property of Carbon?

Carbon is an element of group-14 p-block element which is intended in the first place in the group and shows different anomalous properties. Catenation is the ability of an element through which an element can form long-chain compounds forming covalent bonds with its other elements. As we know carbon exists on earth in various free and combine states and has organic and inorganic compounds. There are various organic compounds formed by carbon atoms due to its catenation property.

2. Why Does the Carbon Element Show Anomalous Behavior?

Carbon atoms show anomalous behavior which is different from other members of the group due to various properties of carbon elements.

Properties responsible for anomalous behavior of carbon are:

•    Higher electronegativity

•    High ionization power

•    Small size of an atom

•    Absence of d-orbital in ca carbon atom

Many properties are different from other elements of the same group shown by carbon atoms and thus it makes carbon a unique element.

These properties are tetravalency, catenation, the small size of the atom, electronegativity.