Question

Draw a Lewis structure for nitrogen pentoxide \(\left(\mathrm{N}_{2} \mathrm{O}_{5}\right)\) in which each \(\mathrm{N}\) is bonded to three \(\mathrm{O}\) atoms.

Short answer

The Lewis structure involves each nitrogen connected to three oxygens, with some double bonds to satisfy the octet rule.

Step-by-step solution

Count Total Valence Electrons

We first calculate the total number of valence electrons available for the \ \( \mathrm{N}_2 \mathrm{O}_5 \ \) molecule. Nitrogen (\ \( \mathrm{N} \ \)) has 5 valence electrons and Oxygen (\ \( \mathrm{O} \ \)) has 6 valence electrons. Thus, the total number of valence electrons is: \\[2 \times 5 + 5 \times 6 = 10 + 30 = 40\]

Arrange Atoms and Build Skeleton

Next, arrange the atoms. Place the nitrogen atoms centrally, connected to each other, and bond each nitrogen atom to three oxygen atoms, trying to accommodate the formula \ \( \mathrm{N}_{2} \mathrm{O}_{5} \ \). A possible arrangement is having central nitrogen atoms with one oxygen lying between them, forming N-O-N bridging. The extra oxygens are terminal.

Connect Atoms with Single Bonds

Start with single bonds between atoms. Each nitrogen atom is bonded to three oxygen atoms. This uses \ \( 8 \ \text{ bonds} \times 2 = 16 \ \text{ electrons} \).

Complete the Octet for Oxygen Atoms

Oxygen requires 8 electrons to fulfill its octet. Each terminal oxygen is currently with 2 electrons from a single bond, so add 6 more electrons in the form of three lone pairs on each terminal oxygen.

Adjust Bonds to Satisfy Nitrogen Octet

In \ \( \mathrm{N}_2 \mathrm{O}_5 \ \), not all nitrogen atoms have a completed octet. To satisfy nitrogen's octet, change some of the nitrogen-oxygen single bonds to double bonds as appropriate. For example, convert the bond involving the bridging oxygen into a double bond and an adjacent bond in the same nitrogen to maintain consistent valence matters.

Verify the Total Electron Count

Ensure that the total electron count of the diagram matches the available 40 valence electrons. Double-check that all nitrogen, as well as oxygen atoms, have a complete octet.

Key concepts

Valence Electrons

Valence electrons are the outermost electrons of an atom and are crucial in chemical bonding. They determine how an atom can bond with others.
For instance, valence electrons can be shared, transferred, or pooled in the formation of molecular structures like nitrogen pentoxide (\(\mathrm{N}_2 \mathrm{O}_5\)).
Identifying the number of valence electrons in a molecule is the first step in drawing a Lewis structure.

• Nitrogen (N) has 5 valence electrons
• Oxygen (O) has 6 valence electrons

For \(\mathrm{N}_2 \mathrm{O}_5\), you add up the valence electrons from all nitrogen and oxygen atoms: \[ 2 \times 5 + 5 \times 6 = 40 \text{ valence electrons} \] Each element uses these electrons to create bonds that hold molecules together.

Octet Rule

The octet rule is a chemical rule of thumb, reflecting the "desire" of atoms to achieve a noble gas configuration, often having eight electrons in their outer shell. In a Lewis structure, this rule guides how atoms share electrons to form stable bonds.

• For nitrogen and oxygen to meet the octet rule, they must use their valence electrons effectively, either through sharing, gaining, or losing electrons.
• Oxygen usually completes its octet by forming two bonds and maintaining two lone pairs.
• Nitrogen often requires forming multiple bonds, like double bonds, to complete its octet.

In nitrogen pentoxide, every nitrogen and oxygen aims to fulfil the octet. Adjusting single bonds to double bonds helps satisfy this condition in the molecule.

Nitrogen Pentoxide

Nitrogen pentoxide (\(\mathrm{N}_2 \mathrm{O}_5\)) is a fascinating molecule in chemistry, known for its involvement in nitration reactions. It consists of two nitrogen atoms linked by an oxygen atom, and each nitrogen atom forms bonds with additional oxygen atoms. In drawing the Lewis structure for \(\mathrm{N}_2 \mathrm{O}_5\), one should account for:

• A total of 40 valence electrons
• Nitrogens at the center, each connected to three oxygens

Adjustments, such as converting single bonds to double bonds, may be necessary to maintain the electron count and ensure all atoms satisfy the octet rule in the structure.

Chemical Bonding

Chemical bonding involves the attraction between atoms or molecules and is fundamental to forming compounds such as nitrogen pentoxide. There are different types of chemical bonds that can appear in a Lewis structure:

• Single bonds involve one pair of shared electrons.
• Double bonds involve two pairs of shared electrons.
• Triple bonds are less common and involve three pairs of shared electrons.

In \(\mathrm{N}_2 \mathrm{O}_5\), chemical bonding is represented by a combination of single and double bonds. Initially, nitrogen atoms form single bonds with oxygen. However, to satisfy octet rules, some bonds become double bonds. Through balancing single and double bonds, the structure aligns with the valence electron count and fulfills each atom's need for a stable electronic configuration.