Draw the structure of NCNH2, where the atoms are connected as shown in the formula. Minimize formal charges and include lone pairs. Sketch the following molecule: NH2CO2H (skeletal structure H2NCOOH, both O atoms attached to C).
The Correct Answer and Explanation is :
Let’s start by analyzing and drawing the structures for both NCNH₂ and NH₂CO₂H.
Structure of NCNH₂
The molecular formula NCNH₂ suggests a linear arrangement of atoms:
- N (nitrogen) at the first position is typically trivalent, forming three bonds.
- C (carbon) in the middle would typically form four bonds.
- NH₂ is an amino group attached to the second nitrogen.
Minimizing formal charges:
- The first nitrogen (N) will form a triple bond with carbon (C) to complete its octet while carrying one lone pair, resulting in a neutral charge.
- The carbon will form a single bond with the second nitrogen (N) and a triple bond with the first nitrogen, satisfying its four bonds.
- The second nitrogen will form a single bond with carbon and will be bonded to two hydrogen atoms (H₂), carrying a lone pair.
Structure of NH₂CO₂H
For NH₂CO₂H, known as glycine in its non-ionic form, the structural arrangement can be understood as:
- NH₂ (amino group) linked to a C (central carbon).
- C also bonded to an O (oxygen) in a double bond (carbonyl group) and another O in a single bond which also has an OH group (carboxyl group).
Minimizing formal charges:
- The nitrogen (N) carries a lone pair and forms three bonds: two with hydrogen atoms and one with the central carbon, making it neutral.
- The central carbon forms four bonds: one with nitrogen, one with the double-bonded oxygen, one with the single-bonded oxygen, and one more with the hydrogen of the OH group.
- The double-bonded oxygen carries two lone pairs, and the single-bonded oxygen of the OH group carries three lone pairs and a single bond with hydrogen.
I’ll now generate an image to depict both molecular structures as described above.
The image above illustrates the molecular structures of NCNH₂ and NH₂CO₂H, designed to show the connectivity of atoms, bond types, and the placement of lone pairs to minimize formal charges.
Explanation of Molecular Structures:
- NCNH₂:
- The first nitrogen (N) is triple-bonded to the central carbon (C), providing stability and minimizing formal charges through the use of a triple bond, allowing for a more stable electronic configuration.
- The second nitrogen (N) is singly bonded to the carbon and carries two hydrogen atoms. It also includes a lone pair, helping to satisfy the valence shell electron pair repulsion (VSEPR) theory for minimal formal charge.
- NH₂CO₂H:
- The amino group (NH₂) is attached to the central carbon, which helps in forming a simple structural base for the molecule.
- The central carbon is doubly bonded to one oxygen (creating a carbonyl group) and singly bonded to another oxygen, which carries an OH group (carboxyl group). This arrangement allows for resonance stabilization in the molecule.
- The inclusion of lone pairs on oxygens and the nitrogen’s lone pair are critical for understanding the electron distribution around these atoms, which affects reactivity and interaction with other molecules.
These structures are pivotal in organic chemistry and biochemistry for understanding molecular interactions, reactivity, and properties. The visual representation helps in grasping the complex nature of molecular architecture and electron arrangements.