Question

Draw \(N, N\)-dimethylethanamine clearly showing the threedimensional perspective at the nitrogen. Use the convention of solid and dashed wedges and include nitrogen's lone pair.

Short answer

Draw the ethane backbone, attach the nitrogen, add two methyl groups, and represent the 3D structure with wedges and lone pair on nitrogen.

Step-by-step solution

Understand the Structure of the Molecule

First, identify the molecular components of N,N-dimethylethanamine. The name indicates an ethane backbone with two methyl groups and an amine group attached to the nitrogen.

Draw the Molecular Backbone

Start by drawing the ethane backbone, which is two carbon atoms singly bonded to each other: CH3-CH2

Add the Nitrogen Atom

Attach the nitrogen atom (N) to the second carbon (C) of the ethane chain to form ethanamine.

Attach the Methyl Groups

Attach two methyl groups (CH3) to the nitrogen atom. The nitrogen now has three bonds: one to the ethane backbone and two to the methyl groups.

Represent the Three-Dimensional Structure

Use the solid wedge to represent the bond coming towards you and a dashed wedge for the bond going away from you. The nitrogen's lone pair should be placed in the appropriate position to maintain tetrahedral geometry. Draw the wedges to show the spatial arrangement around the nitrogen.

Finalize the Drawing

Ensure that the nitrogen atom also displays its lone pair. The final structure should look like this:

Key concepts

Organic Chemistry

Organic chemistry is the branch of chemistry that deals with the structure, properties, and reactions of organic compounds, which contain carbon atoms. One key focus is understanding how these carbon atoms form bonds with hydrogen, oxygen, nitrogen, and other elements.
In the case of N,N-dimethylethanamine, you're dealing with a molecule that includes carbon (C), hydrogen (H), and nitrogen (N) atoms. This compound falls under the category of amines, which are characterized by the presence of a nitrogen atom connected to one or more carbon atoms. Knowing these basics helps in visualizing and constructing the molecule accurately.

Molecular Structure

Molecular structure is all about how atoms in a molecule are arranged and bonded together. For N,N-dimethylethanamine, the name tells us a lot about its structure:

• 'Ethane' implies a backbone of two carbon atoms.
• The 'N,N-dimethyl' part indicates two methyl groups (CH3) attached to a nitrogen atom.

To start, you draw the ethane backbone: two carbon atoms linked with a single bond. Next, attach the nitrogen atom to the second carbon. Finally, add the two methyl groups to this nitrogen.
Remember, the nitrogen in N,N-dimethylethanamine forms three bonds: one with the ethane backbone and two with the methyl groups. This sets you up for considering how these atoms are spatially arranged, leading us to the three-dimensional perspective.

Three-Dimensional Perspective

In organic chemistry, a three-dimensional (3D) perspective is essential for understanding molecular shape and behavior. To properly convey this, we use solid and dashed wedges:

• A solid wedge represents a bond coming towards you.
• A dashed wedge represents a bond going away from you.

For N,N-dimethylethanamine, you need to show the nitrogen atom's three bonds and lone pair in a tetrahedral arrangement. This means:

• One bond points in the plane of the paper.
• One bond comes out of the plane (solid wedge).
• One bond goes into the plane (dashed wedge).
• The nitrogen's lone pair also occupies space in this arrangement.

Using these conventions, you maintain the molecule's realistic 3D shape, which is crucial for predicting physical and chemical properties.

Lone Pairs

Lone pairs are valence electrons that are not involved in bonding. For nitrogen in N,N-dimethylethanamine, this means there is one pair of electrons not bonded to other atoms. Despite not forming bonds, these electrons occupy space and affect the molecule's shape and reactivity.
In a tetrahedral arrangement around nitrogen, these lone pairs take up one of the four positions. This pushes the bonded atoms slightly away, affecting bond angles slightly. In your drawing:

• Three bonds radiate from the nitrogen atom.
• One lone pair completes the tetrahedral structure.

Showing this lone pair in the correct position is key for accurately representing the molecule. It also helps in understanding how the molecule might interact with other substances in chemical reactions.