electrochemistry

oxidation

loss of electrons

reduction

gain of electrons

oxidizing agent

species that is reduced

reducing agent

species that is oxidized

anode

the site of oxidation

cathode

the site of reduction

disproportionation reactions

a redox reaction in which the same species is both oxidized and reduced

oxidation states

1. Elements in their elemental form are in the zero oxidation state

2. Group 1 metals are +1 and Group 2 are +2 in compounds

3. Hydrogen is +1 except when bonded to a metal only (when it’s -1)

4. transition elements must be determined from anion’s charge (except Al = 3, Zn = 2, Cd = 2, Ag = 1)

5. the most electronegative elements get their typical oxidation state

6. The last element is assigned balance the charge of the compound/ion

electrochemical cells

1. the anode is always the site of oxidation

2. the cathode is always the side of reduction

3. electrons always flow from anode to cathode

galvanic (voltaic) cells

spontaneous

produce electricity

anode (-) —> cathode (+)

Functions as batteries

electrolytic cells

nonspontaneous

consume electricity

anode (+) to cathode (-)

produce elements