Welcome to your study guide on Lewis dot structures, molecular geometry, and the octet rule! These foundational concepts are crucial in understanding chemical bonding and the three-dimensional shapes of molecules.

🖼️ Lewis Dot Structures

Lewis dot structures visually represent the valence electrons of atoms within a molecule which play a key role in chemical bonding. These structures are an efficient way to display the valence electrons of an atom. Each dot represents a valence electron while long lines between two atoms are bonding electrons.

🎯 Valence Electrons

What are valence electrons? They’re the electrons located in an atom’s outermost shell, therefore making them the electrons located farthest from the nucleus.

Lewis dot structures represent valence electrons as dots around the chemical symbol of an element. Take a look at a few in the image below!

An image showing valence electrons as dots around elemental symbols.

Image courtesy of eCampusOntario

✏️ Drawing Lewis Structures

Here are some steps you can follow to draw a Lewis structure:

1. Determine the Total Number of Valence Electrons: For neutral molecules, add up valence electrons from each atom. For ions, add or remove electrons according to charge.
2. Choose a Central Atom: Usually the least electronegative atom, except hydrogen which is never central.
3. Draw Skeletal Structure: Connect atoms with single bonds initially.
4. Distribute Remaining Electrons as Lone Pairs: Firstly to outer atoms until they achieve octets, then to central atom.
5. Rearrange into Double/Triple Bonds if Necessary: If there are not enough electrons for central atom to achieve an octet.

Image needed: Step-by-step diagrams of drawing Lewis structures for water (H₂O) and carbon dioxide (CO₂).

Advanced Topics:

• Resonance Structures: Some molecules can be represented by two or more valid Lewis structures called resonance forms.