Redox Reactions Flashcards
When do redox reactions occur?
When electrons are transferred from the atom that becomes oxidised to the atom that becomes reduced
What is oxidation?
Loss of electrons, becoming + charged
What is reduction?
Gain of electrons, becoming - charged
What is the oxidation state?
Either the actual chan=rage of the monoatomic ion, or a hypothetical charge assigned to the atom
What is the oxidation number for an atom in its elemental form?
0
What is the oxidation number for any monatomic ion?
Equal to the charge of the ion, e.g Na+ = +1
What is the oxidation number for nonmetals?
Usually have negative oxidation numbers , e.g. oxygen = -2 but hydrogen = +1
What is the oxidation number in neutral compounds?
0
What is the oxidation number for fluorine?
-1
What’s the oxidation number for group 1 elements?
+1
What is the oxidation number for group 2 elements?
+2
What is the oxidation number for hydrogen with nonmetals?
+1
What is the oxidation number for hydrogen with metals?
-1
What are the 2 exceptions for oxygens oxidation number?
When bound to fluorine or in a peroxide
In oxidation half reactions, where are electrons presented?
As the products
In reduction half reactions, how are electrons presented?
As reactants
How do you balance equations by the method of half reactions?
1- Assign oxidation states (who is gaining e- and who is losing e-)
2- Divide the reaction into 2 half reactions
3- Balance each half reactions
4- Multiply the half reactions by whole numbers
5- Add 2 half reactions together and simplify
