1. Chemical Bonding
Chp , 7.3, 8.1

2. A chemical bond is a force that holds two atoms together.
Bonding Basics
A chemical bond is a force that holds two atoms together.
Valence electrons are involved in the formation of chemical bonds between two atoms.
Octet Rule-atoms are stable with eight valence electrons in the outer energy level. (except H and He)
Elements tend to react to acquire the stable electron configuration of an unreactive noble gas: ns2p6

3. ionic covalent metallic Starts with a metal atom
Ends with a nonmetal atom
Starts with a nonmetal atom
You have a metal from the periodic table

4. Ionic Bonding
Review: Electronegativity is the ability to attract and pull on electrons.
A metal atom with very low electronegativity comes in contact with a nonmetal atom that has a very high electronegativity. Therefore the nonmetal will pull the electron away from the metal.
A cation forms when metal atom loses one or more valence electrons to attain a noble gas configuration. Groups 1 and 2 metals are the most reactive because it is easy to lose 1 or 2 valence electrons.
A anion forms when a nonmetal atom gains one or more valence electrons to attain a noble gas configuration. Group 6 and 6 are the most reactive because it is easy to gain 1 or 2 valence electrons.
Electrostatic force bonds the ions together

6. Covalent Bonding Sharing is Caring!
Nonmetal atoms of similar electronegativity combine to form a covalent bond: “sharing” of electrons.
If the sharing of the electrons in the bond is “equal” then a nonpolar covalent bond forms.
Diatomic elements! Electrons are equally shared. Both atoms have the same pull on the electrons.
7 Diatomic Elements: H2, N2, O2, F2, Cl2, Br2, I2
If the sharing of the electrons in the bond is “unequal” then a polar covalent bond forms.
Two different nonmetals! Electrons are unequally shared. One atom has a greater pull on the electrons.
everages

7. In a covalent bond, the net attraction between positive nucleus and negative electrons is greater than the net repulsion between 2 electrons or 2 nuclei.

8. Metallic Bonding
For metal atoms, the electrons are not tied to a specific nucleus so they are free to move creating a model that looks like an array of positive nuclei surrounded in a sea of electrons. It is important to understand that we use the term metallic bonding and not metallic bond. The bonding in metals is collective and not a single bond between one metal atom and another metal atom.
A metallic bonding is the attraction of metal cations for delocalized electrons.