Oxidation and Reduction its all about the electron

Oxidation and Reduction …it’s all about the electron…

Oxidation and reduction are opposite processes. It’s all about XIDATION the electron! O I L R I G s OSS of ELECTRONS EDUCTION s AIN of ELECTRONS

For example… Reduction…the gain of electrons. e- e- e- A e- Oxidation…the loss of electrons. ee- e- B e-

Losing electrons to oxygen is common… Oxidation…the addition of oxygen… Reduction…the loss of oxygen… O A O …and loss of electons! O B O …and gain of electons!

To figure out whether an element is oxidized or reduced, 0 Oxidation state: Hg(l) A number that shows the total number of electrons an element has gained or lost to be in its present state -1 +2 F 2 O(aq) -2 +1 OH (aq) first you must determine the element’s oxidation state.

To figure out whether an element is oxidized or reduced, Determining “Oxidation State” …an ACTIVITY! first you must determine the element’s oxidation state.

Guideline 1: 0 Na(s) 0 H 2(g) 0 Hg(l) It’s easy for uncombined elements: we always assume the oxidation state to be zero.

Guideline 2: +1 -1 Na. Cl(s) +3 -1 Cr. Cl 3(s) +1 -1 H 2 O 2(aq) For neutral compounds: the sum of the oxidation states is zero. ***don’t forget to multiply by the subscripts!***

Guideline 3: +5 -2 PO 4 3 -(aq) +2 2+ Hg (aq) -2 +1 OH (aq) For ions: the sum of the oxidation states is overall charge on the ion.

Guideline 4: -1 +2 F 2 O(aq) -2 +1 OH (aq) +1 -1 H 2 O 2(aq) The most electronegative element will have the negative charge.

Guideline 1 2 e n i l e d i Gu OXIDATION ide line Bringing it 3 Oxidation ALL together. State REDUCTION Guideline 4 electrons Gu

Now that we know oxidation state, we can tell whether an element is oxidized or reduced in a reaction. 0 0 +3 -2 2 Fe(s) + 3 O 2(g) 2 Fe 2 O 3(s) OIL RIG Oxidized – loses electrons: Iron is oxidized Reduced – gains electrons: Oxygen is reduced

Oxidizing and Reducing Agents …opposites again! Oxidizing agent – the element that’s reduced Reducing agent – the element that’s oxidized Let’s look back at our reaction equation.

A closer look… RUSTING! 0 0 +3 -2 2 Fe(s) + 3 O 2(g) 2 Fe 2 O 3(s) Iron loses electrons: oxidized reducing agent Oxygen gains electrons: reduced oxidizing agent

Summary… REDOX Reduction Gain of electrons Oxidizing agent Oxidation Loss of electrons Reducing agent …and all of this can be determined by finding the oxidation state!