BellRinger What are valence electrons? Remember that a molecule is a group of atoms that are bonded together. What do you think causes atoms to stick together?

BellRinger Predict the type of bond that will occur between an H atom and an H atom. Draw the Lewis dot structure of the bond. Write the chemical formula for this bond based on your prediction.

Agenda NOTES: Bonding Valence Electrons & Bonding Octet Rule Ionic Bonding by Electron Transfer Covalent Bonding by Electron Sharing

Bonds A bond is a connection between atoms. Without bonds, molecules would fall apart.

Valence Electrons Remember that valence electrons are the ones found on the outside ring of an atom. Valence electrons are the key to understanding why atoms bond.

Octet Rule Atoms want to have enough electrons to “fill up” their valence shell. Since most atoms need 8 electrons to fill the outer ring, this is called the octet rule* * Hydrogen [H] and Helium [He] only need 2 electrons to fill the valence level.

2 Types of Bonds Bonds are created when valence electrons are rearranged to create octets There are 2 types of bonds Ionic Covalent

Ionic Bonds Ionic bonds occur between a metal and a nonmetal The metal transfers electrons to the nonmetal Losing electrons causes one atom to become positively charged, while the atom gaining electrons becomes negatively charged. Because they are now oppositely charged, the atoms/ions stick together.

K F _ + The ionic bond is the attraction between the positive K+ ion and the negative F- ion + _ K F

Static Cling is LIKE Ionic Bonding

Covalent Bonds Covalent bonds occur between nonmetals. Like ionic bonds, atoms form covalent bonds in order to gain an octet (8 valence electrons) Instead of one gaining or losing, a pair of valence electrons is shared between them.

How will two chlorine atoms react? Cl Cl

Cl Cl Cl Cl Cl

Cl Cl The octet is achieved by each atom sharing the electron pair in the middle

Holding Hands is LIKE Covalent Bonding

IONIC AND COVALENT Animations Link for animations: https://www.schooltube.com/video/80f7d9bb582fb58 b547d/

_ Cl + F K IONIC COVALENT

Assignments 9 Review Questions Ionic vs Covalent Venn Diagram