Unit 3 Oxidation States Oxidation State Oxidation Number

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