Let's break down the questions **step by step** and provide detailed solutions. --- ## **3. Orbital Interactions** ### **a. Which orbital interaction(s) (A, B, C, D, E) are best classified as σ interactions?** **Sigma (σ) bonds** occur when orbitals overlap along the internuclear axis (end-to-end). - **A:** Two s orbitals overlap end-to-end (σ) - **B:** An s and a p orbital overlap end-to-end (σ) - **E:** Two p orbitals overlap end-to-end (σ) **Answer:** **A, B, E** --- ### **b. Which orbital interaction(s) (A, B, C, D, E) are best classified as π interactions?** **Pi (π) bonds** occur when p orbitals overlap side-by-side (above and below the axis). - **C:** Two p orbitals overlap side-by-side (π) - **D:** Two p orbitals overlap side-by-side, but out of phase (antibonding π*) **Answer:** **C, D** --- ### **c. Ethylene (H₂C=CH₂):** #### **i. Which orbital interaction(s) (A, B, C, D, E) best describe the C–H bonds of ethylene?** - **C–H bonds** are **σ bonds** formed by the overlap of an sp² (from C) and s (from H). So, **A (s-s overlap)** and **B (s-p overlap)** best represent this. **Answer:** **A, B** #### **ii. Which orbital interaction(s) (A, B, C, D, E) best describe the C–C bonds of ethylene?** - Ethylene has a **double bond (C=C)**: - One **σ bond** (sp²-sp² overlap, which is like E: p-p end-to-end) - One **π bond** (p-p side-by-side, like C) **Answer:** **C (π bond), E (σ bond)** #### **iii. Draw the orbital interactions that contribute to the C–C bonds of ethylene.** **Draw directly on the diagram:** - Draw a **σ bond** as an end-to-end overlap between two sp² orbitals along the axis. - Draw a **π bond** as a side-by-side overlap (above and below the plane) between two unhybridized p orbitals. --- ## **4. Skeletal Structures of Amino Acids** ### **Aspartic acid (HO₂CCH₂CH(NH₂)CO₂H)** - Draw a chain: O=C-OH | CH₂ | CH(NH₂) | COOH ### **Isoleucine (CH₃CH₂CH(CH₃)CH(NH₂)CO₂H)** - Draw a backbone: COOH—CH(NH₂)—CH(CH₃)—CH₂—CH₃ ### **Lysine (NH₂(CH₂)₄CH(NH₂)CO₂H)** - Draw a backbone: COOH—CH(NH₂)—(CH₂)₄—NH₂ --- ## **5. Resonance Forms of Compound A** - Move the negative charge and double bonds around the ring according to resonance rules. - Each resonance form should move the negative charge and the double bond by one position. - Show all lone pairs, formal charges, and curved arrows for electron movement. --- ### **Summary Table** | Question | Answer | |---------------------|-----------------------------------------------------| | 3a (σ interactions) | **A, B, E** | | 3b (π interactions) | **C, D** | | 3c (C-H bonds) | **A, B** | | 3c (C-C bonds) | **C, E** | | 4 (structures) | Draw skeletal structures as described above | | 5 (resonance) | Draw 3 resonance forms with charges/arrows shown | --- ### **Visuals** **(If you need the drawings for #4 and #5, let me know and I'll provide those structures as images!)** Let me know if you need direct drawings for any part!