Match the following Atoms with their respective covalency.

Atom		Covalency
a.	Oxygen	i.	1
b.	Carbon	ii.	2
c.	Chlorine	iii.	3
d.	Nitrogen	iv.	4

The correct answer is Option 2: a - ii, b - iv, c - i, d - iii.

Key Points

• Oxygen has a covalency of 2, as it generally forms two covalent bonds to complete its octet (e.g., H₂O).
• Carbon has a covalency of 4, as it forms four covalent bonds to complete its octet (e.g., CH₄).
• Chlorine has a covalency of 1, as it typically forms one covalent bond (e.g., HCl).
• Nitrogen has a covalency of 3, as it commonly forms three covalent bonds (e.g., NH₃).
• Covalency refers to the number of covalent bonds an atom can form to achieve a stable electronic configuration.

Additional Information

• Covalency: The covalency of an atom is determined by the number of electrons it can share to achieve a stable electronic configuration (usually completing its octet).
• Octet Rule: Atoms tend to form bonds until they have eight electrons in their valence shell, which makes them stable.
• Examples:
  • Oxygen forms two bonds in water (H₂O).
  • Carbon forms four bonds in methane (CH₄).
  • Chlorine forms one bond in hydrogen chloride (HCl).
  • Nitrogen forms three bonds in ammonia (NH₃).
• Exceptions: Some elements may exhibit variable covalency depending on the compounds they form (e.g., phosphorus, sulfur).
• Periodic Trends: Covalency is influenced by the number of valence electrons and the position of the element in the periodic table.