Textbook Question
Assign oxidation numbers to each element in the following ions. (c) C2O4 2-
Ch.22 - The Main Group Elements
Chapter 22, Problem 114
Draw all the possible resonance structures for N2O and assign formal charges. Which resonance structure makes the greatest contribution to the resonance hybrid?
Verified step by step guidance1
Step 1: Identify the total number of valence electrons in N2O. Nitrogen (N) has 5 valence electrons and Oxygen (O) has 6 valence electrons. Calculate the total by adding the valence electrons of two nitrogen atoms and one oxygen atom.
Step 2: Draw the skeletal structure of N2O. Typically, the least electronegative atom is placed in the center, so arrange the atoms as N-N-O.
Step 3: Distribute the electrons to satisfy the octet rule for each atom, starting with the terminal oxygen atom, then the central nitrogen, and finally the terminal nitrogen. Use single, double, or triple bonds as necessary.
Step 4: Draw all possible resonance structures by moving electrons to form different bonding arrangements while keeping the total number of electrons constant. Ensure each structure adheres to the octet rule where possible.
Step 5: Calculate the formal charge for each atom in each resonance structure using the formula: Formal Charge = (Valence Electrons) - (Non-bonding Electrons) - 0.5*(Bonding Electrons). Identify the resonance structure with the smallest formal charges and the most negative charge on the most electronegative atom (oxygen) as the major contributor to the resonance hybrid.
Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Resonance Structures
Resonance structures are different Lewis structures for a molecule that can be drawn by moving electrons around while keeping the positions of the atoms fixed. These structures represent the same molecule and contribute to the overall resonance hybrid, which is a more accurate depiction of the molecule's electron distribution. The actual structure is a blend of all possible resonance forms, and the stability of each form affects its contribution to the hybrid.
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Resonance Structures
Formal Charge
Formal charge is a theoretical charge assigned to an atom in a molecule, calculated by taking the number of valence electrons in the free atom, subtracting the number of non-bonding electrons, and half the number of bonding electrons. It helps in determining the most stable resonance structure, as structures with formal charges closest to zero are generally more favorable. Understanding formal charges is crucial for evaluating the relative stability of different resonance forms.
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Resonance Hybrid
The resonance hybrid is the actual structure of a molecule that is a weighted average of all its resonance structures. It reflects the delocalization of electrons across the molecule, leading to increased stability. The resonance hybrid is more stable than any individual resonance structure, and the contribution of each structure to the hybrid depends on factors like formal charge distribution and overall stability.
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