Problem 21 - 43 Years JEE ADVANCED (1978-2020) + JEE MAIN Chapterwise & Topicwise Solved Papers Chemistry

Question

The total number of electrons that take part in forming the bond in \(\mathrm{N}_{2}\) is [1980] (a) 2 (b) 4 (c) 6 (d) 10

Step-by-Step Solution

Answer

6 electrons participate in \(\mathrm{N}_2\) bond formation.

Step 1: Understand the Molecular Formula

The molecular formula for nitrogen gas is \(\mathrm{N}_2\). This indicates that there are two nitrogen atoms bonded together in a molecule of nitrogen gas.

Step 2: Recall the Valence Electrons in a Nitrogen Atom

Each nitrogen atom has 5 valence electrons because it's in Group 15 of the periodic table. These are the electrons that can participate in bond formation.

Step 3: Describe the Bond Formation in \(\mathrm{N}_2\)

In a nitrogen molecule \(\mathrm{N}_2\), the two nitrogen atoms form a triple bond. This means three pairs of electrons (6 electrons total) are shared between the two nitrogen atoms.

Step 4: Count the Electrons Used in Bond Formation

In the formation of a triple bond, a total of 6 electrons are shared between the nitrogen atoms. Therefore, 6 electrons take part in forming the bonds.

Key Concepts

Valence Electrons in Nitrogen

Valence electrons are the electrons present in the outermost shell of an atom. They are crucial because they are the electrons involved in forming bonds with other atoms. For nitrogen, which is found in Group 15 of the periodic table, there are 5 valence electrons. These electrons exist in the second energy level, which is the outermost shell for nitrogen.

• Outermost Shell: The shell farthest from the nucleus, crucial for bonding.
• Group 15: Indicates the number of valence electrons for nitrogen, which is 5.

Understanding the role of valence electrons helps us comprehend how atoms interact and bond, as these are the electrons that nitrogen uses when forming bonds with other atoms. This behavior of seeking to complete its octet or 8-electron configuration plays a significant role in the chemistry of nitrogen.

Triple Bond in N_2 Molecule

In the nitrogen molecule \(\mathrm{N}_2\), the two nitrogen atoms are bonded together by a triple bond. A triple bond occurs when three pairs of electrons are shared between two atoms. This type of bond is one of the strongest and most stable because of the significant electron sharing involved.

• Three Pairs of Electrons: Equivalent to six electrons, shared between two atoms.
• Strong and Stable: Triple bonds provide extra strength to the molecule.

The formation of this triple bond satisfies the octet rule for nitrogen, allowing each nitrogen atom to "feel" as if it has eight electrons in its valence shell, thereby achieving stability. The concept of a triple bond demonstrates the lengths that atoms will go to in order to achieve a stable electron configuration, showcasing the versatility and adaptability of molecular bonding.

Electron Sharing in Nitrogen Bond

Electron sharing is a fundamental concept in chemical bonding, and for nitrogen \(\mathrm{N}_2\), it is crucial. Each nitrogen atom shares three of its five valence electrons with the other nitrogen atom, resulting in mutual benefit. This forms what we call a covalent bond, characterized by shared pairs of electrons.

• Covalent Bond: Formed by sharing electrons between atoms.
• Mutual Benefit: Both atoms get closer to fulfilling the octet rule.

By sharing electrons, each nitrogen atom gains access to more electrons, helping to fill its valence shell. This sharing results in a more stable molecule and highlights the importance of covalent bonding in molecular structures. Understanding how electron sharing works not only in nitrogen but in all molecules is key to understanding chemical reactions and the formation of compounds.