What are the other two reasons for choosing (b) in Example 9.7? Example 9.7 Formaldehyde (CH 2 O), a liquid with a disagreeable odor, traditionally has been used to preserve laboratory specimens. Draw the most likely Lewis structure for the compound. Strategy A plausible Lewis structure should satisfy the octet rule for all the elements, except H, and have the formal charges (if any) distributed according to electronegativity guidelines. Solution The two possible skeletal structures are First we draw the Lewis structures for each of these possibilities: To show the formal charges, we follow the procedure given in Example 9.6. In (a) the C atom has a total of five electrons (one lone pair plus three electrons from the breaking of a single and a double bond). Because C has four valence electrons, the formal charge on the atom is 4 − 5 = −1. The O atom has a total of five electrons (one lone pair and three electrons from the breaking of a single and a double bond). Because O has six valence electrons, the formal charge on the atom is 6 − 5 = +1. In (b) the C atom has a total of four electrons from the breaking of two single bonds and a double bond, so its formal charge is 4 − 4 = 0. The O atom has a total of six electrons (two lone pairs and two electrons from the breaking of the double bond). Therefore, the formal charge on the atom is 6 − 6 = 0. Although both structures satisfy the octet rule, (b) is the more likely structure because it carries no formal charges. Check In each case make sure that the total number of valence electrons is 12. Can you suggest two other reasons why (a) is less plausible?
What are the other two reasons for choosing (b) in Example 9.7? Example 9.7 Formaldehyde (CH 2 O), a liquid with a disagreeable odor, traditionally has been used to preserve laboratory specimens. Draw the most likely Lewis structure for the compound. Strategy A plausible Lewis structure should satisfy the octet rule for all the elements, except H, and have the formal charges (if any) distributed according to electronegativity guidelines. Solution The two possible skeletal structures are First we draw the Lewis structures for each of these possibilities: To show the formal charges, we follow the procedure given in Example 9.6. In (a) the C atom has a total of five electrons (one lone pair plus three electrons from the breaking of a single and a double bond). Because C has four valence electrons, the formal charge on the atom is 4 − 5 = −1. The O atom has a total of five electrons (one lone pair and three electrons from the breaking of a single and a double bond). Because O has six valence electrons, the formal charge on the atom is 6 − 5 = +1. In (b) the C atom has a total of four electrons from the breaking of two single bonds and a double bond, so its formal charge is 4 − 4 = 0. The O atom has a total of six electrons (two lone pairs and two electrons from the breaking of the double bond). Therefore, the formal charge on the atom is 6 − 6 = 0. Although both structures satisfy the octet rule, (b) is the more likely structure because it carries no formal charges. Check In each case make sure that the total number of valence electrons is 12. Can you suggest two other reasons why (a) is less plausible?
Solution Summary: The author explains the two Lewis structures for formaldehyde labelled as ‘a’ and ‘b’ in example 9.7 of the book.
What are the other two reasons for choosing (b) in Example 9.7?
Example 9.7
Formaldehyde (CH2O), a liquid with a disagreeable odor, traditionally has been used to preserve laboratory specimens. Draw the most likely Lewis structure for the compound.
Strategy A plausible Lewis structure should satisfy the octet rule for all the elements, except H, and have the formal charges (if any) distributed according to electronegativity guidelines.
Solution The two possible skeletal structures are
First we draw the Lewis structures for each of these possibilities:
To show the formal charges, we follow the procedure given in Example 9.6. In (a) the C atom has a total of five electrons (one lone pair plus three electrons from the breaking of a single and a double bond). Because C has four valence electrons, the formal charge on the atom is 4 − 5 = −1. The O atom has a total of five electrons (one lone pair and three electrons from the breaking of a single and a double bond). Because O has six valence electrons, the formal charge on the atom is 6 − 5 = +1. In (b) the C atom has a total of four electrons from the breaking of two single bonds and a double bond, so its formal charge is 4 − 4 = 0. The O atom has a total of six electrons (two lone pairs and two electrons from the breaking of the double bond). Therefore, the formal charge on the atom is 6 − 6 = 0. Although both structures satisfy the octet rule, (b) is the more likely structure because it carries no formal charges.
Check In each case make sure that the total number of valence electrons is 12. Can you suggest two other reasons why (a) is less plausible?
The cyanate ion (OCN-) and the fulminate ion (CNO-) share the same three atoms but have vastly different properties. The cyanate ion is stable, while the fulminate ion is unstable and forms explosive compounds. The resonance structures of the cyanate ion were explored in Example 5.6. Draw Lewis structures for the fulminate ion—including possible resonance forms—and use formal charge to explain why the fulminate ion is less stable(and therefore more reactive) than the cyanate ion.
Consider the image of the P4 molecule provided and answer the following:
1. Are there any lone pairs of electrons present in the P4 molecule. It is advisable to draw the Lewis structure.
2. How many P-P bonds are present in the molecules.
3. Draw a Lewis structure for a linear P4 molecule, that would satisfy the octet rule.
4. Determine whether this linear structure has any resonance structures. If so, show all possibilities.
5. By calculating formal charges, explain which of the two structures, the linear molecule or the tetrahedral molecule would be more stable.
Carbon disulfide is a colorless, volatile, highly flammable liquid with a very unpleasant smell that is used as a solvent in some laboratory applications. The formula for carbon disulfide is CS2. Formal charges can be used to decide whether its connectivity is more likely to be C–S–S or S–C–S.
Part1: Add any nonzero formal charges to the atoms as applicable for the Lewis structure shown with connectivity C–S–S. All valence electrons have been included, and this structure follows the octet rule. If formal charges are equal to zero, they should not be included.
Part2: Add any nonzero formal charges to the atoms as applicable for the Lewis structure shown with connectivity C–S–S. All valence electrons have been included. If formal charges are equal to zero, they should not be included. (This structure is a resonance form of the structure in Part 1.)
part 3: Add any nonzero formal charges to the atoms as applicable for the Lewis structure shown with connectivity S–C–S. All valence…
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, chemistry and related others by exploring similar questions and additional content below.
Author:Steven D. Gammon, Ebbing, Darrell Ebbing, Steven D., Darrell; Gammon, Darrell Ebbing; Steven D. Gammon, Darrell D.; Gammon, Ebbing; Steven D. Gammon; Darrell
Author:Steven D. Gammon, Ebbing, Darrell Ebbing, Steven D., Darrell; Gammon, Darrell Ebbing; Steven D. Gammon, Darrell D.; Gammon, Ebbing; Steven D. Gammon; Darrell