Chemical Bonding

Chemical Bonds Chemical Bond: a mutual attraction between the nuclei and valence electrons of different atoms that bonds atoms together. Valence electrons: electrons available to be gained lost or shared to form chemical bonds. Located in the outer most s and p orbitals

Valance Electrons Calcium? Bromine? Aluminum?

Types of Bonds Covalent bond: results from the sharing of electron pairs between two atoms Ionic bond: results from the attraction between positively and negatively charged atoms Metallic bond: results from an attraction between metal atoms and a surrounding sea of electrons

Ionic Bonds Atoms can gain or lose electrons to have a complete outer shell of electrons (valence electrons). Metals always lose electron and become positive. Aluminum has 3 valence e-. It will lose all its e- to have a +3 charge Nonmetals always gain electrons and become negative. Oxygen has 6 valence electrons. It will gain 2 e- to have 8 e- to have a -2 charge.

Charges N? Li? C? Cl?

Polar Bonds Polar: an uneven distribution of charge Polar-Covalent Bond: a covalent bond in which the bonded electrons are shared unequally Nonpolar-Covalent Bond: a covalent bond with a balanced sharing of electrons

What type of bond?? You can determine if a bond is nonpolar-covalent, polar-covalent, or ionic by looking at the difference in electronegativity. What is electronegativity? What does difference mean? Turn to pg 151 in your textbook.

Electronegativity Values

What type of bond?? A difference of < .5 A difference of .5 ≤ x < 2.0 A difference of ≥ 2.0

What type of bond?? Sulfur and Hydrogen? Bromine and Potassium? Cesium and Phosphorus? Sodium and Chlorine?