MP Board · Class 10 · Science · Carbon and its CompoundsExplain the formation of covalent bonds in carbon with the help of examples. Why is carbon able to form such a large number of compounds? Discuss the two main properties responsible for this.

Introduction to Covalent Bonding in Carbon\nCarbon has an atomic number of 6, which means its electronic configuration is 2, 4. To achieve a stable noble gas configuration (like neon, which has 8 electrons in its outermost shell), carbon needs either to gain four electrons to form $C^{4-}$ anion or lose four electrons to form $C^{4+}$ cation.

• Why ionic bonding is not possible:

  • Gaining four electrons would make it difficult for the nucleus with 6 protons to hold onto 10 electrons.
  • Losing four electrons requires a large amount of energy to remove four electrons, leaving behind a carbon cation with 6 protons holding on to just 2 electrons.

• Formation of Covalent Bonds:

  • To overcome this energy barrier, carbon shares its four valence electrons with other atoms of carbon or other elements like hydrogen, oxygen, chlorine, nitrogen, etc.
  • The bond formed by the mutual sharing of electron pairs is known as a covalent bond. For example, in a methane molecule ($CH_4$), one carbon atom shares its four valence electrons with four hydrogen atoms, resulting in stable octet for carbon and duplet for hydrogen.

Why Carbon Forms a Large Number of Compounds (Versatile Nature)\nCarbon forms millions of organic compounds, far more than any other element. This versatility is primarily due to two distinct properties:

1. Catenation (श्रृंखलन):

   • Catenation is the unique ability of carbon atoms to link with one another through covalent bonds to form long chains, branched chains, and closed rings of various sizes.
   • Carbon-carbon bonds are very strong and stable due to the small size of the carbon atom, which enables the nucleus to hold the shared pair of electrons strongly.
   • Silicon also forms compounds with hydrogen (silanes) up to chains of seven or eight atoms, but these compounds are very reactive and unstable compared to carbon compounds.

2. Tetravalency (चतुःसंयोजकता):

   • Carbon has a valency of four, meaning it is capable of bonding with four other carbon atoms or atoms of monovalent elements such as hydrogen, oxygen, nitrogen, sulfur, halogens, etc.
   • Due to its small size, the nucleus can hold the shared electron pairs effectively, making the compounds formed with other elements exceptionally stable.
   • This allows carbon to form diverse compounds with specific functional groups, giving rise to an extensive variety of carbon compounds with unique physical and chemical properties.