Write the complete Lewis structure for (a) formaldehyde, HCHO, which as its aqueous solution "formalin" is used to preserve biological specimens; (b) methanol, \(\mathrm{CH}_{3} \mathrm{OH}\), the toxic compound also called wood alcohol; (c) glycine, \(\mathrm{CH}_{2}\left(\mathrm{NH}_{2}\right) \mathrm{COOH}\), the simplest of the amino acids, the building blocks of protcins.

Valence electrons are the outermost electrons of an atom and are crucial in determining how an element interacts and bonds with other elements. In chemistry, these electrons are represented by dots surrounding the atomic symbols in Lewis structures. For example, hydrogen has one valence electron, which is why it's often depicted with a single dot when drawing Lewis structures.

Carbon, with four valence electrons, is commonly shown with four dots, while oxygen, which has six valence electrons, is represented with six dots. In the context of formaldehyde (HCHO), methanol (CH3OH), and glycine (CH2(NH2)COOH), calculating the total valence electrons is the initial step to predicting the molecule's structure. It is essential to correctly count the valence electrons to ensure that we create accurate and stable molecular structures.

The electron octet rule is a staple in understanding chemical bonding and structure. It states that atoms tend to form bonds until they are surrounded by eight electrons in their highest energy level, or valence shell, which is the arrangement seen in noble gases. This rule guides us to predict the typical bonding patterns for most elements, except hydrogen and helium, which are stable with a 'duet' of two electrons.

When applying the octet rule to create Lewis structures for molecules like formaldehyde, methanol, and glycine, we aim to ensure that each carbon, nitrogen, and oxygen atom attains a full octet, while the hydrogen atoms reach the duet. This rule is a key factor when determining whether to form single, double, or triple bonds within the molecule. For instance, the double bond between carbon and oxygen in formaldehyde fulfills the octet rule for both atoms.

In chemistry, formal charges help us understand the distribution of electrons within a molecule and can indicate the stability of the structure. A formal charge is the charge an atom would have if all bonding electrons were equally shared between the bonded atoms. It's calculated based on the number of valence electrons an atom has, minus the electrons assigned to the atom in the Lewis structure (both bonding and nonbonding electrons).

The formula for calculating the formal charge is: \( FC = V - (N + \frac{B}{2}) \) where \( FC \) is the formal charge, \( V \) is the number of valence electrons, \( N \) is the number of non-bonding electrons, and \( B \) is the number of bonding electrons. Our goal in drawing Lewis structures for molecules is to minimize formal charges, achieving a more stable configuration. This optimization often results in the most commonly observed structure in nature. For example, if formal charges are present in the final Lewis structure of formaldehyde, methanol, or glycine, they should balance out to reflect the real-world neutrality of these molecules.