Understanding Oxidation and Reduction
* Oxidation: Loss of electrons. The oxidation number of an element increases.
* Reduction: Gain of electrons. The oxidation number of an element decreases.
The Reaction
The reaction between lithium (Li) and bromine (Br₂) produces lithium bromide (LiBr):
2 Li(s) + Br₂(l) → 2 LiBr(s)
Analyzing Oxidation States
* Lithium (Li):
* Starts as elemental lithium, with an oxidation state of 0.
* In LiBr, it becomes Li⁺, with an oxidation state of +1. This means lithium has *lost* an electron, so it has been oxidized.
* Bromine (Br₂):
* Starts as elemental bromine, with an oxidation state of 0.
* In LiBr, it becomes Br⁻, with an oxidation state of -1. This means bromine has *gained* an electron, so it has been reduced.
Summary
* Lithium is oxidized. It loses an electron and its oxidation state increases from 0 to +1.
* Bromine is reduced. It gains an electron and its oxidation state decreases from 0 to -1.
