Lewis Structures and Chemical

Bonding

Valence Electrons

The electrons that exist in the outermost electron shell of an atom

We can determine the number of valence electrons by drawing out electron configuration diagrams OR by looking at periodic table groups

Because Oxygen is in group 6, it has 6 valence electrons

Lewis Dot Structures

Lewis Dot Structures are diagrams that show how many valence electrons an atom of an element has

These structures also help show bonding between elements

To draw a lewis dot structure, you need to first know how many valence electrons an atom has

Nitrogen has 5 valence electrons so you will have 5 dots in your diagram

How to Draw the Lewis Dot

Structure for Cl

Determine the Element’s Atomic

Symbol

Determine how many valence

electrons Cl has

Start by drawing one dot at the top and move around the symbol counter clockwise until you’ve used up all of your available valence electrons

Chemical Bonding

What is Chemical Bonding?

The attraction between atoms that allows for the formation of chemical substances that contain two or more atoms

Covalent Bonding

Bond in which one or more pairs of electrons are shared by two atoms

Water (H2O)Carbon Dioxide

(CO2)

How We Determine

Covalent BondsAtoms are “happiest” when they have 8 valence electrons

If an atom has less than 8 valence electrons, it will try and bond with atoms that fulfill those 8 valence electrons

Oxygen has 6 valence electrons, so it needs to find 2 more valence electrons to complete its outer shell

Hydrogen happens to have 1 valence electron

Oxygen bonds with 2 hydrogen atoms to complete its outer shell to form H2O (water)

The lines between H and O represent the sharing of an electron

Ionic BondingBond in which one or more electrons from one atom are removed and attached to another atom, resulting in positive and negative ions which attract one another