What is the lowest energy alternative resonance structure for this compound:
-HC-N+///N
/
H3C
Where /// is a triple bond connecting N+ and N
These boards don't handle spaces so you can't draw structural formulas. You will need to do line formulas.
CH3CH2CH(OH)CH2CtriplebondN or something like that.
CH3-CH-N<triple bond>N
There is a negative charge on CH and a positive charge on the central N
To determine the lowest energy alternative resonance structure for the given compound, we need to consider the rules of resonance and the stability of the resulting structures. Let's break down the process:
1. Identify and count the valence electrons:
The compound contains three carbon atoms, one nitrogen atom with a positive charge, one triple bond between the two nitrogen atoms, and three hydrogen atoms. Carbon has four valence electrons, nitrogen has five, and hydrogen has one. Therefore, the total number of valence electrons is:
3 (carbon) + 1 (positive charge on nitrogen) + 3 (hydrogen) = 7
2. Determine the possible Lewis structures:
Based on the given compound, the Lewis structure can be represented as:
-HC-N+///N
/
H3C
3. Construct the alternative resonance structures:
In resonance, we can move electrons to create multiple alternative structures while maintaining the same overall connectivity. In this case, we can move the electrons around the triple bond:
-HC-N=N+///N
/
H3C
Now the electrons are distributed differently, with one double bond between the nitrogen atoms and an unshared electron on the positively charged nitrogen atom.
4. Evaluate the stability of the resonance structures:
To assess the stability of the resonance structures, we can consider the concept of formal charges. Formal charge is calculated by comparing the number of valence electrons in an atom's isolated state with its number of non-bonding electrons and half of the bonding electrons.
In the original structure, the nitrogen with a positive charge has a formal charge of +1, while the terminal nitrogen atom has a formal charge of -1. However, in the alternative resonance structure, the formal charges changed. The nitrogen with a double bond and the positive charge has a formal charge of +2, while the terminal nitrogen atom has a formal charge of -2.
Formal charges are most stable when they approach zero or are minimized. Therefore, the alternative resonance structure with formal charges closest to zero is usually the favored or lowest energy structure.
In this case, since the original structure had formal charges of +1 and -1, while the alternative resonance structure had formal charges of +2 and -2, the lowest energy resonance structure for this compound is the original structure:
-HC-N+///N
/
H3C
Therefore, the lowest energy alternative resonance structure is the same as the given compound.