Table of contents

1. A Review of General Chemistry5h 5m
2. Molecular Representations1h 14m
3. Acids and Bases2h 46m
4. Alkanes and Cycloalkanes4h 17m
5. Chirality3h 39m
6. Thermodynamics and Kinetics1h 22m
7. Substitution Reactions1h 48m
8. Elimination Reactions2h 30m
9. Alkenes and Alkynes2h 9m
10. Addition Reactions3h 19m
11. Radical Reactions1h 58m
12. Alcohols, Ethers, Epoxides and Thiols2h 42m
13. Alcohols and Carbonyl Compounds2h 17m
14. Synthetic Techniques1h 26m
15. Analytical Techniques:IR, NMR, Mass Spect7h 3m
16. Conjugated Systems6h 13m
17. Ultraviolet Spectroscopy51m
18. Aromaticity2h 34m
19. Reactions of Aromatics: EAS and Beyond5h 1m
20. Phenols55m
21. Aldehydes and Ketones: Nucleophilic Addition4h 56m
22. Carboxylic Acid Derivatives: NAS2h 51m
23. The Chemistry of Thioesters, Phophate Ester and Phosphate Anhydrides1h 10m
24. Enolate Chemistry: Reactions at the Alpha-Carbon1h 53m
25. Condensation Chemistry2h 9m
26. Amines1h 43m
27. Heterocycles2h 0m
28. Carbohydrates5h 53m
29. Amino Acids4h 20m
30. Peptides and Proteins2h 42m
31. Catalysis in Organic Reactions1h 30m
32. Lipids 2h 50m
33. The Organic Chemistry of Metabolic Pathways2h 52m
34. Nucleic Acids1h 32m
35. Transition Metals6h 14m
36. Synthetic Polymers1h 49m

1. A Review of General Chemistry

Formal Charges

Organic Chemistry

1. A Review of General Chemistry

Formal Charges

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3:47 minutes

Problem 17e

Textbook Question

Draw the Lewis structure for each of the following:
e. CH₃N⁺H₃

Verified step by step guidance

Step 1: Identify the total number of valence electrons in the molecule. Carbon (C) has 4 valence electrons, each hydrogen (H) has 1 valence electron, nitrogen (N) has 5 valence electrons, and the positive charge indicates the loss of one electron. Calculate the total valence electrons: (4 from C) + (3 × 1 from H) + (5 from N) + (3 × 1 from H) - 1 (positive charge).

Step 2: Determine the central atom. Carbon (C) is typically the central atom in organic molecules, as it can form multiple bonds. Place the carbon atom in the center and attach three hydrogen atoms to it.

Step 3: Attach the nitrogen atom to the carbon atom with a single bond. Then, attach three hydrogen atoms to the nitrogen atom. This accounts for the CH3 group bonded to NH3.

Step 4: Distribute the remaining valence electrons around the atoms to satisfy the octet rule for carbon and nitrogen. Hydrogen atoms only need 2 electrons to complete their valence shell, which is already satisfied by their bonds.

Step 5: Ensure the positive charge is represented in the structure. Since the molecule is CH3NH3+, the nitrogen atom will have a formal positive charge due to the loss of one electron. Verify that all atoms have the correct number of electrons and the structure reflects the positive charge.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Lewis Structures

Lewis structures are diagrams that represent the bonding between atoms in a molecule and the lone pairs of electrons that may exist. They use dots to represent electrons and lines to represent bonds, allowing chemists to visualize the arrangement of atoms and the distribution of electrons. Understanding how to draw Lewis structures is essential for predicting molecular geometry and reactivity.

Formal Charge

Formal charge is a concept used to determine the distribution of electrons in a molecule. It is calculated by taking the number of valence electrons in an atom, subtracting the number of non-bonding electrons, and half the number of bonding electrons. This helps in assessing the stability of a Lewis structure, as structures with formal charges closest to zero are generally more stable.

Cation Structure

A cation is a positively charged ion formed when an atom loses one or more electrons. In the case of CH3NH3+, the presence of a positive charge indicates that the molecule has one fewer electron than protons. Understanding how to account for this charge when drawing the Lewis structure is crucial, as it affects the overall electron count and the arrangement of atoms.