Draw the missing lone-pair electrons and assign the missing formal charges for the following:
a.
b.

Verified step by step guidance

1. Step 1: Analyze the given structure. The molecule consists of a carbon atom bonded to three hydrogen atoms and an oxygen atom. The oxygen atom is also bonded to a hydrogen atom.
2. Step 2: Recall that oxygen typically has two lone pairs of electrons in its neutral state. Add two lone pairs to the oxygen atom to complete its octet.
3. Step 3: Calculate the formal charge for each atom. Use the formula: Formal charge = (Valence electrons) - (Non-bonding electrons) - (Bonding electrons / 2). For oxygen, valence electrons = 6, non-bonding electrons = 4 (two lone pairs), and bonding electrons = 4 (two bonds).
4. Step 4: Verify the formal charge for carbon. Carbon typically has a formal charge of 0 when it forms four bonds. In this structure, carbon is bonded to three hydrogens and one oxygen, satisfying its octet.
5. Step 5: Confirm the formal charge for hydrogen atoms. Hydrogen typically has a formal charge of 0 when it forms one bond. Each hydrogen atom in the structure is bonded to either carbon or oxygen, which is consistent with this rule.

Key Concepts

Lone Pair Electrons

Lone pair electrons 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 how to identify and represent lone pairs is essential for accurately drawing Lewis structures and predicting molecular shapes.

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 non-bonding electrons, and half the number of bonding electrons. It helps in assessing the stability of a molecule and determining the most favorable Lewis structure. Assigning formal charges correctly is vital for understanding the distribution of electrons in a molecule.

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 provide a visual representation of the arrangement of electrons and help predict molecular geometry and reactivity. Mastery of drawing Lewis structures is fundamental in organic chemistry for analyzing molecular interactions and properties.