Question

Three equivalent resonance structures can be drawn for a nitrate ion. How much of the time does the bonding in a nitrate ion match any one of them?

Short answer

Answer: 33.33%

Step-by-step solution

Determine the Total Number of Resonance Structures

For a nitrate ion, there are three equivalent resonance structures.

Calculate the Fraction of Time Aligned with One Resonance Structure

There are a total of three identical resonance structures, and we want to find the percentage of time that any one of them represents the actual bonding in the nitrate ion. To find this, we can simply divide one (as for one structure) by the total number of resonance structures (three, in this case). The fraction of time represented by one resonance structure is: Fraction = 1/3

Convert the Fraction to Percentage

To convert the fraction to a percentage, we can simply multiply it by 100. Percentage = Fraction × 100 Percentage = (1/3) × 100 = 33.33% Thus, the bonding in a nitrate ion matches any one of the three equivalent resonance structures about 33.33% of the time.

Key concepts

Nitrate Ion

The nitrate ion, often expressed as \(NO_3^-\), is a negatively charged polyatomic ion that plays a crucial role in various chemical and environmental processes. Understanding the structure of a nitrate ion is critical in comprehending more complex chemical reactions where nitrates are involved. Each nitrogen atom in the nitrate ion forms a central point that bonds with three oxygen atoms. The total charge of the nitrate ion is -1, and this charge distribution is stabilized by the presence of multiple resonance structures.

• The nitrate ion is a polyatomic ion composed of one nitrogen atom and three oxygen atoms.
• It carries an overall negative charge, indicated by the superscript '−'.
• Resonance structures are a way to represent the delocalization of electrons within this ion, contributing to its stability.

These resonance structures reflect the diversity of ways electrons can pair around the nitrogen and oxygen atoms, ensuring the ion can be represented in different forms. However, no individual resonance structure fully accounts for the true bonding within the nitrate ion. Instead, these structures together portray a hybrid depiction of its real electron configuration.

Chemical Bonding

Chemical bonding in the nitrate ion is complex yet fascinating, exhibiting a perfect example of resonance. The idea of resonance is fundamental in chemistry, particularly when explaining how electrons share between atoms. In the nitrate ion, each oxygen atom forms a bond with the nitrogen atom. However, instead of having distinct single or double bonds, the bonds between nitrogen and oxygen fluctuate. To illustrate this concept, chemists use "resonance structures." These structures are essentially snapshots of electron distribution possibilities.

• Resonance involves multiple valid Lewis structures for a particular molecule or ion.
• In nitrate, resonance structures distribute bonds differently across oxygen atoms, enhancing stability.
• The true global structure is a blend of these resonance forms.

Resonance structures, therefore, allow us to reflect on the true nature of electron distribution, indicating bonds are neither entirely single nor double, but somewhere in between. They contribute to a deeper understanding of chemical stability and bonding behavior.

Percentage Calculation

Calculating the percentage helps us quantify the dominance or representation of each resonance structure in the overall resonance hybrid. For the nitrate ion, with its three equally valid resonance structures, understanding what fraction of time the ion resembles any one structure can be insightful.The percentage calculation is straightforward: we first find the fraction of time one structure represents the true nitrate ion by dividing 1 by 3, the total number of resonance structures. This gives us a fraction of \(\frac{1}{3}\). To express this fraction as a percentage, multiply it by 100. Thus, \(\frac{1}{3} \times 100 = 33.33\%\).This indicates that each resonance structure represents the chemical bonding in nitrate ion approximately 33.33% of the time. This percentage calculation showcases the concept of blending multiple structures to form the best representation of the actual molecular entity.