Draw in all missing lone pairs for the following molecules.
(b)

Verified step by step guidance

1. Step 1: Identify atoms in the molecule that typically have lone pairs. Oxygen atoms are the most common atoms to have lone pairs in organic molecules.
2. Step 2: Analyze the structure. The molecule contains three oxygen atoms: one in a hydroxyl group (-OH), one in a carbonyl group (C=O), and one as part of a carboxylate group (-COO⁻).
3. Step 3: Assign lone pairs to the hydroxyl group (-OH). The oxygen in the hydroxyl group has two lone pairs because it is bonded to one hydrogen atom and follows the octet rule.
4. Step 4: Assign lone pairs to the carbonyl group (C=O). The oxygen in the carbonyl group has two lone pairs because it is double-bonded to carbon and follows the octet rule.
5. Step 5: Assign lone pairs to the carboxylate group (-COO⁻). The negatively charged oxygen in the carboxylate group has three lone pairs because the negative charge indicates an extra electron, and the other oxygen in the carboxylate group has two lone pairs as it is double-bonded to carbon.

Key Concepts

Lone Pairs

Lone pairs are pairs of valence electrons that are not involved in bonding and are localized on a single atom. They play a crucial role in determining the geometry and reactivity of molecules. Understanding where to place lone pairs is essential for accurately representing molecular structures and predicting molecular behavior.

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 help visualize the arrangement of electrons and are fundamental for understanding molecular geometry, resonance, and reactivity. Drawing complete Lewis structures, including all lone pairs, is vital for analyzing chemical properties.

Formal Charge

Formal charge is a theoretical charge assigned to an atom in a molecule, calculated based on the number of valence electrons, the number of bonds, and the number of lone pairs. It helps in assessing the stability of a molecule and determining the most favorable Lewis structure. Minimizing formal charges across a molecule often leads to more stable configurations.