1 / 8

Oxidation Numbers

Oxidation Numbers. p.232-234. Assigning Oxidation Numbers. Oxidation Number : positive or negative number assigned to an atom according to a set of rules. Rules for Assigning Oxidation Numbers. The oxidation number of any free element is 0 - Na or O 2

lisle
Télécharger la présentation

Oxidation Numbers

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Oxidation Numbers p.232-234

  2. Assigning Oxidation Numbers • Oxidation Number: positive or negative number assigned to an atom according to a set of rules

  3. Rules for Assigning Oxidation Numbers • The oxidation number of any free element is 0 - Na or O2 • The oxidation number of a monatomic ion is equal to the charge on the ion. Some atoms have several possible oxidation numbers. - Iron can be Fe2+ or Fe3+

  4. Rules for Assigning Oxidation Numbers • The oxidation number of each hydrogen atom in most of its compounds is +1, EXCEPT in metal hydrides (LiH) where it is -1. • The oxidation number of oxygenIN A COMPOUND is -2, EXCEPT in peroxides (H2O2) where it is -1.

  5. Rules for Assigning Oxidation Numbers • The sum of the oxidation numbers of ALL THE ATOMS in a particle must equal the apparent charge of that particle. SO42-, S2O32-, Na2SO4 • In compounds, the elements of Group 1, 2, and aluminum have positive oxidation #’s of +1, +2, and +3 respectively. AlBr3, CaO

  6. Now you try some! • Find the oxidation numbers of iodine in HIO4, HIO3, HIO, HI • Section Review p. 235 #1 a-i

  7. Oxidation-number Changes in Chemical Reactions • If the oxidation number increases for an atom • Oxidation has occurred • If the oxidation number decreases for an atom • Reduction has occurred 2AgNO3(aq) + Cu(s)  Cu(NO3)2(aq) + 2Ag(s) • What is being oxidized? What is being reduced? +1 +5 –2 0 +2 +5 –2 0

  8. Now you try some! • Use the changes in oxidation numbers to identify which atoms are oxidized, and which atoms are reduced: 2H2 (g) + O2 (g)  2H2O (l) 2KNO3 (s)  2KNO2 (s) + O2 (g) NH4NO3 (s)  N2 (g) + 2H2O (g) (HINT: consider each N separately) PbO2 (aq) + 4HI (aq)  I2 (aq) + PbI2 (s) + 2H2O (l)

More Related