Unit 3: Oxidation States –Oxidation State = Oxidation Number = Valence Number - the charge left on an atom or ion after it has lost or gained electrons in order to obtain a stable structure. –the way that elements combine depends upon the outer (valence) electrons. –atoms or ions react in order to become stable. –a stable arrangement generally means that the atom or ion has an octet in their outer shell (8 electrons with the exception of He which has 2 valence e-).

–Some elements like to lose e- to become stable like the metals. –Some elements like to gain e- to become stable like the nonmetals. –When atoms lose or gain electrons they form ions. –Ion - a charged particle. 1) cation = (+) charged particle 2) anion = (-) charged particle –When metals lose e- they become (+) and these (+) ions are called cations. –When nonmetals gain e- they become (-) and these (-) ions are called anions.

–the charge left on the atom or ion after it reacts is called the oxidation state. –the oxidation state of some elements (s and p sections of the P. Table) can be figured out, while the other sections (d and f sections) must be memorized. –page 2 of your packet we will refer to often (only includes the s and p sections. –the most stable elements on the P. Table are the Noble or Inert gases (Group VIIIA). –other atoms react to get the stable arrangement of Group VIIIA.

–For sections s and p Group # = # valence e-. Group IA = 1 valence e- metals = lose e-, therefore this entire group likes to lose 1 e- to become stable. when they lose 1 e- they form a +1 charge! –1) Nomenclature = naming When = only one possible (+) ox. state. How = element’s name ion. (ex) H 1+ = hydrogen ion (ex) Li 1+ = lithium ion (ex) K 1+ = potassium ion

Group IIA = 2 valence e- metals that have 2 e- to lose, therefore forming a 2+ ion. (ex) Be 2+ = beryllium ion (ex) Ca 2+ = calcium ion (ex) Sr 2+ = strontium ion Group IIIA = 3 valence e- metals that have 3 e- to lose, therefore forming a 3+ ion. (ex) B 3+ = boron ion (ex) Al 3+ = aluminum ion