Write reasonable Lewis structures for the following species, none of which follow the octet rule. (a) \(\mathrm{BeH}_{2}\) (b) \(\mathrm{CO}^{-}\) (c) \(\mathrm{SO}_{2}^{-}\) (d) \(\mathrm{CH}_{3}\)

Question: Draw the Lewis structures for the following chemical species that do not follow the octet rule: (a) BeH2, (b) CO-, (c) SO2-, and (d) CH3. Explain the formation of each structure and the presence of any resonance structures. Answer: (a) BeH2 Lewis structure: ``` H | Be - H ``` Beryllium has only 4 electrons around it, fulfilling its valence requirement, which is less than the octet rule. Both hydrogens have filled their valence requirement (2 electrons each). (b) CO- Lewis structure has two resonance forms: ``` Resonance Form1: C ≡ O Resonance Form2: C = O: :O ``` The actual structure is an average of the two resonance structures, with a single negative charge on carbon. (c) SO2- Lewis structure: ``` O=S=O .S ``` The structure has a total of 19 valence electrons, with the central sulfur atom forming a radical species. (d) CH3 Lewis structure: ``` H | H-C-H . ``` Carbon has only 7 electrons around it, breaking the octet rule.