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CHEM - 2.1.4 - 2.1.5 Acids and Redox > Redox > Flashcards

Flashcards in Redox Deck (7)
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Oxidation number

- Based on a set of rules that apply to atoms, and can be thought of as the number of electrons involved in bonding to a different element.



Oxidation Is Loss of electrons; Reduction Is Gain of electrons
- Reducing agents: gives electrons to another substance and becomes oxidised.
- Oxidising agent: removes electrons from another substance and becomes reduced.


Oxidation rules for elements

- Oxidation no. is always 0 for elements.
- In pure element, any bonding is to atoms of same element.
- So in H2, O2, Na and Fe oxidation no. of each atom of the element is 0.


Oxidation rules for compounds and ions

- Each atom in a compound has an oxidation no.
- An oxidation no. has a sign which is placed BEFORE the no.
- Oxidation no. is numerically the same as ionic charge.


Special cases for ox. no.

H in metal hydrides= -1
O in peroxides= -1
O bonded to F= +2


Rule for combined atoms:

Sum of the oxidation no. = total charge


Redox in terms of oxidation no.

- Reduction is DECREASE in ox. no.
- Oxidation is INCREASE in ox. no.