Question

Distinguish among single, double, and triple bonds in a molecule, and give an example of each.

Short answer

A single bond shares one pair of electrons, double bond shares two pairs, and triple bond shares three pairs. Examples are hydrogen gas (H_2) for single bond, carbon dioxide (CO_2) for double bond, and nitrogen gas (N_2) for triple bond.

Step-by-step solution

Defining Bond Types

A single bond in a molecule is where one pair of electrons are shared between two atoms. In contrast, a double bond shares two pairs of electrons between two atoms and a triple bond is the sharing of three pairs of electrons between two atoms.

Examples: Single Bonds

A good example of a molecule with a single bond is hydrogen gas (H_2), where two hydrogen atoms are linked by sharing one pair of electrons.

Examples: Double Bonds

For double bonds, consider carbon dioxide (CO_2). In this molecule, each oxygen atom shares two pairs of electrons with the central carbon atom, creating two double bonds.

Examples: Triple Bonds

An example of a molecule with a triple bond is nitrogen gas (N_2). Here, two nitrogen atoms share three pairs of electrons to form a triple bond.

Key concepts

single bond

In chemistry, a single bond is a basic type of covalent bond found in many molecules. This kind of bond occurs when two atoms share one lonely pair of electrons. Imagine they are like dance partners, with the electrons being the music that holds the pair together. You can spot a single bond in simple molecules like hydrogen gas (H\(_2\)).
In hydrogen gas, two hydrogen atoms come together and each brings along one electron to create a shared "pair". This pairing stabilizes the atoms, essentially allowing them to reach a lower energy state. Some other examples of molecules with single bonds include:

• Water (H\(_2\)O) - in each of the O-H bonds, one pair of electrons is shared.
• Methane (CH\(_4\)) - each C-H bond is a single bond.

While single bonds are the simplest form of bonding, they are essential for forming the backbone of more complex molecules.

double bond

Double bonds are another fascinating aspect of chemical bonding. They happen when two atoms share two pairs of electrons instead of just one pair. This kind of bond can be thought of as a stronger and shorter cousin of the single bond.
An easy example of a double bond can be found in carbon dioxide (CO\(_2\)).
Here, each carbon-oxygen bond consists of two pairs of shared electrons. This setup not only brings atoms closer but also makes the molecule more rigid compared to single bonds.

• These bonds often contribute to a molecule's reactivity.
• They influence the molecule's shape due to electron pair repulsion.

In addition to carbon dioxide, molecules like ethene (C\(_2\)H\(_4\)) also showcase double bonds, specifically between the carbon atoms.

triple bond

Triple bonds represent one of the strongest interactions between two atoms in a molecule. In a triple bond, three pairs of electrons are shared between two atoms, creating an even more intimate connection than double bonds.
A classic example of a molecule with a triple bond is nitrogen gas (N\(_2\)).
This bond is famously difficult to break because of its strength and stability. In fact, nitrogen gas makes up over three-quarters of Earth's atmosphere largely due to the stability of these triple bonds.

• Triple bonds are found in molecules like acetylene (C\(_2\)H\(_2\)) where the carbon atoms share three pairs of electrons.
• This sharing of three electron pairs results in a linear geometry for the bonded atoms.

Given their robustness, breaking a triple bond requires a lot of energy, making them crucial in industrial applications and biological systems.