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Ch.8 - Basic Concepts of Chemical Bonding
Chapter 8, Problem 78

A new compound is made that has a C—N bond length of 118 pm. Is this bond likely to be a single, double, or triple C—N bond?

Verified step by step guidance
1
Step 1: Understand the typical bond lengths for C—N bonds. Single, double, and triple bonds have different bond lengths due to the number of shared electron pairs. Generally, single bonds are the longest, and triple bonds are the shortest.
Step 2: Recall the approximate bond lengths for C—N bonds: a single C—N bond is typically around 147 pm, a double C—N bond is around 130 pm, and a triple C—N bond is around 116 pm.
Step 3: Compare the given bond length of 118 pm to the typical bond lengths for C—N bonds. Determine which bond type the given length is closest to.
Step 4: Consider the nature of bond lengths: shorter bond lengths indicate stronger bonds due to more shared electrons, which is characteristic of multiple bonds (double or triple).
Step 5: Based on the comparison, infer whether the bond is more likely to be a single, double, or triple bond.

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Bond Length

Bond length is the average distance between the nuclei of two bonded atoms. It is influenced by the type of bond formed; single bonds are generally longer than double bonds, which in turn are longer than triple bonds. Understanding bond lengths helps in determining the nature of the bond between atoms.
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Average Bond Order

Types of Covalent Bonds

Covalent bonds can be classified as single, double, or triple based on the number of shared electron pairs between atoms. A single bond involves one pair of shared electrons, a double bond involves two pairs, and a triple bond involves three pairs. Each type of bond has characteristic bond lengths, with single bonds being the longest and triple bonds the shortest.
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Bonding Types

Electronegativity and Bond Character

Electronegativity refers to the ability of an atom to attract shared electrons in a bond. In a C—N bond, the difference in electronegativity between carbon and nitrogen can influence the bond's character and length. Understanding how electronegativity affects bond formation is essential for predicting bond types and their corresponding lengths.
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Metallic Character Example