Question

A common trait of simple organic compounds is to have Lewis structures where all atoms have a formal charge of zero. Consider the following incomplete Lewis structure for an organic compound called methyl cyanoacrylate, the main ingredient in Super Glue. Draw a complete Lewis structure for methyl cyanoacrylate in which all atoms have a formal charge of zero.

Short answer

The complete Lewis structure for methyl cyanoacrylate, where all atoms have a formal charge of zero, is as follows: H N O | || || H-C-C=N-C-C=O | H In this structure, hydrogen atoms form one bond, all carbon atoms have 4 bonds, nitrogen has three bonds and one lone pair, and oxygen has two bonds and two lone pairs, satisfying the formal charge of zero requirement and the octet rule for all atoms in the molecule.

Step-by-step solution

Formal Charge and Valence Electrons

Before we begin, let's go over the concept of formal charge: Formal charge = (Valence Electrons of an atom) - (electrons assigned to an atom in a molecule). To achieve a formal charge of zero for all atoms in the molecule, we need to make sure that the number of valence electrons assigned to each atom is equal to the number of valence electrons that the element has in its neutral state.

Identify the Elements and Count Valence Electrons

First, identify the elements in the methyl cyanoacrylate molecule. Here, we have carbon (C), hydrogen (H), oxygen (O), and nitrogen (N). Their valence electrons are as follows: - Carbon (C): 4 valence electrons - Hydrogen (H): 1 valence electron - Oxygen (O): 6 valence electrons - Nitrogen (N): 5 valence electrons

Arrange Atoms Based on Formal Charge of Zero Requirement

Now, we will rearrange the structure of methyl cyanoacrylate considering the valence electrons of each element. In drawing the Lewis structure, keep in mind that hydrogen always forms only one bond, and the octet rule applies to other atoms. Follow these steps: 1. Start with the carbon atoms as the backbone of the molecule. 2. Arrange the hydrogen atoms, forming bonds with the carbon atoms such that each hydrogen has one bond, and the carbon atoms achieve their octet rule (4 bonds or 8 electrons). 3. Add the nitrogen and oxygen atoms to form the molecule structure, ensuring that the atoms follow their octet rule (with the exception of hydrogen).

Complete Lewis Structure of Methyl Cyanoacrylate

Here is the Lewis structure for methyl cyanoacrylate, all atoms have a formal charge of zero: H N O | || || H-C-C=N-C-C=O | H In the final structure of methyl cyanoacrylate, hydrogen atoms form one bond, all carbon atoms have 4 bonds, nitrogen has three bonds and one lone pair, and oxygen has two bonds and two lone pairs, thus satisfying the formal charge of zero requirement and the octet rule for all atoms present in the molecule.

Key concepts

Formal Charge

The concept of formal charge is essential in understanding the distribution of electrons in molecules. It can be calculated using the formula:
Formal charge = (Valence electrons of an atom) - (electrons assigned to an atom in a molecule) Typically, for stability, we strive to have a formal charge of zero for each atom within a molecule. In organic compounds, such as methyl cyanoacrylate, achieving a formal charge of zero helps ensure that the molecule is as stable as possible. To accomplish this, electrons are distributed in such a way that the number of valence electrons is equal to the number of electrons assigned through bonds or lone pairs. This distribution can guide the creation of a molecule's Lewis structure.

Valence Electrons

Valence electrons are the electrons on an atom that are available for bonding. They play a critical role in the formation of chemical bonds in molecules. The number of valence electrons that each element has is a key factor in determining its chemical properties and behavior during bond formation. For instance, carbon always has 4 valence electrons, while hydrogen has 1, oxygen has 6, and nitrogen has 5. Understanding how many valence electrons are in play allows chemists and students alike to predict how atoms will bond together to form molecules, such as in the drawing of the Lewis structure for methyl cyanoacrylate.

Octet Rule

The octet rule states that atoms tend to form compounds in ways that give them eight electrons in their valence shell, achieving a configuration similar to that of noble gases. This rule applies to most of the elements, the notable exception being hydrogen, which is content with a duet (two electrons) due to its smaller size. In drawing the Lewis structure of a molecule like methyl cyanoacrylate, the octet rule acts as a guide to ensure that atoms such as carbon, nitrogen, and oxygen fulfill this requirement, leading to a more stable electron configuration.

Organic Compounds

Organic compounds are primarily composed of carbon atoms along with hydrogen, oxygen, nitrogen, and other elements. The defining feature of these compounds is the presence of carbon-carbon and carbon-hydrogen bonds. In the context of a Lewis structure, illustrating organic compounds involves displaying the bonding patterns and electron sharing between these atoms, which is indicative of their structural features and reactivity. Methyl cyanoacrylate is an example of an organic compound used in adhesives like Super Glue.

Methyl Cyanoacrylate

Methyl cyanoacrylate is the main ingredient in Super Glue and is an organic compound composed of carbon, hydrogen, oxygen, and nitrogen atoms. Drawing its Lewis structure is a clear way to understand its molecular composition and chemical bonding. As you have seen from the solution, with careful distribution of valence electrons, all atoms achieve a formal charge of zero, and apart from hydrogen, the other atoms follow the octet rule. The ability of this compound to rapidly polymerize in the presence of water, a process which is intrinsically related to its molecular structure, makes it an effective adhesive.