Topics

• Valence electrons
• Octet rule
• Formal charge
• Drawing molecules

What to Focus On

Lewis structures are one of the most important skills to have before day one. Every mechanism, every reaction, and every discussion of reactivity starts with drawing a molecule. The goal here is fluency, not just accuracy — being able to draw structures quickly keeps the bigger picture in focus.

Formal charge is the detail most often skipped and most often needed. Being able to calculate it quickly matters, since it appears in nearly every chapter.

Why It Matters

Nearly every chapter in organic chemistry begins with structure.

Students who are comfortable drawing Lewis structures often find later topics much easier.

Recommended Resources

Reading

OpenStax Chemistry 2e

• Chapter 7

Videos

• Khan Academy — Lewis diagrams and formal charge
• OCT — Lewis structures and formal charge

Gentle Exercises

Draw:

• CH₄
• NH₄⁺
• NO₃⁻

Determine:

• Formal charges
• Double bonds
• Resonance possibilities

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