Draw Lewis structures for the following organic molecules:
propyne $\left(\mathrm{CH}_3 \mathrm{CCH}\right)$, .

Write Lewis structures for these ions: (a) $\mathrm{O}_2^{2-}$, (b) $\mathrm{C}_2^{2-}$, (c) $\mathrm{NO}^{+}$, (d) $\mathrm{NH}_4^{+}$. Show formal charges.

Draw Lewis structures for the following organic molecule: benzoic acid $\left(\mathrm{C}_6 \mathrm{H}_5 \mathrm{COOH}\right)$. (To draw $\mathrm{C}_6 \mathrm{H}_5 \mathrm{COOH}$, replace an $\mathrm{H}$ atom in benzene with a $\mathrm{COOH}$ group.)

Draw Lewis structures for the following organic molecules:
butadiene $\left(\mathrm{CH}_2 \mathrm{CHCHCH}_2\right)$.

Draw Lewis structures for the following organic molecules:
propane $\left(\mathrm{C}_3 \mathrm{H}_8\right)$.

Describe the hybrid orbitals used by the central atom(s) and the type(s) of bonds formed in

FNO;

Place the species below in order of the shortest to the longest nitrogen-oxygen bond. $\mathrm { H } _ { 2 } \mathrm { NOH } , \quad \mathrm { N } _ { 2 } \mathrm { O } , \quad \mathrm { NO } ^ { + } , \quad \mathrm { NO } _ { 2 } ^ { - } , \quad \mathrm { NO } _ { 3 } ^ { - } \\ \left( \mathrm { H } _ { 2 } \mathrm { NOH } \text { exists as } \mathrm { H } _ { 2 } \mathrm { N } - \mathrm { OH } . \right)$

Draw Lewis structures for the following organic molecules:
tetrafluoroethylene $\left(\mathrm{C}_2 \mathrm{~F}_4\right)$.

Which of the following species are isoelectronic: $\mathrm{NH}_4^{+}, \mathrm{C}_6 \mathrm{H}_6, \mathrm{CO}, \mathrm{CH}_4, \mathrm{~N}_2$, and $\mathrm{B}_3 \mathrm{~N}_3 \mathrm{H}_6$ ?

Explain the difference between the Lewis structure concept and VB theory.

Attempts to prepare $\mathrm{CF}_2, \mathrm{LiO}_2, \mathrm{CsCl}_2$, and $\mathrm{Pl}$ as stable species under atmospheric conditions have failed. Suggest possible reasons for the failure.

Two mice are heterozygous for albinism (Aa). The dominant allele (A) codes for normal pigmentation, and the recessive allele (a) codes for no pigmentation. What percentage of their offspring would have an albino phenotype?

The amide group plays an important role in determining the structure of proteins:

$$<smiles>CNC(C)=O</smiles>$$

Draw another resonance structure for this group. Show formal charges.

Write Lewis structures for $\mathrm{BrF_3}$, $\mathrm{ClF_5}$, and $\mathrm{IF_7}$. Identify those in which the octet rule is not obeyed.