Question

Draw each of the following alkyl groups: (a) methyl (b) ethyl

Short answer

Methyl: \( \text{CH}_3- \); Ethyl: \( \text{CH}_3\text{CH}_2- \)

Step-by-step solution

Understand Alkyl Groups

Alkyl groups are derived from alkanes by removing one hydrogen atom. They are denoted by replacing the 'ane' in the alkane with 'yl', such as methyl from methane.

Recall the Methane Structure

Methane (CH₄) is the simplest alkane, consisting of one carbon atom bonded to four hydrogen atoms. A methyl group is formed by removing one hydrogen atom from methane.

Draw the Methyl Group

The methyl group, CH₃, is a group containing one carbon atom bonded to three hydrogen atoms. It can be depicted as: \[ \text{CH}_3- \] where it can attach to another group at the free valency (the dash).

Recall the Ethane Structure

Ethane (C₂H₆) consists of two carbon atoms, each bonded to three hydrogen atoms and a single bond connecting the two carbons. An ethyl group is formed by removing one hydrogen from the ethane molecule.

Draw the Ethyl Group

The ethyl group, C₂H₅, consists of two carbon atoms bonded together, with the first carbon also bonded to two hydrogen atoms and the second carbon to three hydrogen atoms. It can be depicted as: \[ \text{CH}_3\text{CH}_2- \] with a free valency (the dash) to attach to another group.

Key concepts

Understanding Alkyl Groups

Alkyl groups play a crucial role in organic chemistry as they serve as building blocks for constructing more complex molecules. These groups are essentially hydrocarbon chains derived from alkanes, which are the simplest form of hydrocarbons comprised of carbon and hydrogen atoms solely connected by single bonds. When an alkane loses a hydrogen atom, it transforms into an alkyl group. This loss creates a site known as a free valency, marked by a dash, where the group can bond to other atoms or groups.

• The simplest alkyl group derives from methane, resulting in a methyl group.
• As the chain length increases, more diverse alkyl groups, like ethyl, propyl, and butyl, are formed.

Recognizing and understanding alkyl groups is vital, as they influence the physical properties, reactivity, and applications of organic compounds. Whether in pharmaceuticals, plastics, or fuels, alkyl groups are ubiquitous throughout organic chemistry.

What is a Methyl Group?

The methyl group is the smallest and simplest alkyl group, consisting of one carbon atom bonded to three hydrogen atoms. It's derived from methane (CH₄) by the removal of one hydrogen atom, forming CH₃-. This leaves a free valency, or "open end," where the methyl group can attach to other atoms or groups to form various organic molecules.

• Formula: CH₃-
• Structure resembles a small pyramid, with the carbon at the center and hydrogens radiating out.

When the methyl group attaches to a larger molecule, it can alter the molecule's chemical behavior. For instance, it can change how the molecule interacts with other substances, its solubility in water or oil, and even its boiling and melting points. Thus, the presence of a methyl group can significantly impact the molecular characteristics and functions.

Understanding the Ethyl Group

The ethyl group is the next step up in complexity from the methyl group. It is composed of two carbon atoms and five hydrogen atoms, derived from ethane (C₂H₆) by the removal of a hydrogen atom. The structure of this group is represented as CH₃CH₂-, with the dash indicating the open valency for further chemical attachment.

• Formula: C₂H₅-
• Composed of a two-carbon chain, where the first carbon is bonded to two hydrogens and the second carbon to three hydrogens.

The ethyl group is more versatile than the methyl group due to its larger size and additional carbon atom. It can be found in various organic molecules, contributing to their physical and chemical properties. Such is its significance, that ethyl groups are prevalent in numerous substances, from alcohol (ethanol) to many industrial and biological chemicals, underscoring their importance in chemistry.