The loss of one or more electrons from an atom is called
a. oxidation
c. electrochemistry
b. reduction
d. half-reaction

a. oxidation

Explanation:

Oxidation reaction is defined as the reaction in which a substance looses its electrons. The oxidation state of the substance increases.

Electrochemistry is the branch of science which deals with the interconversion of electrical and chemical changes in the systems.

Reduction reaction is defined as the reaction in which a substance gains electrons. The oxidation state of the substance gets reduced.

Half reaction is a reaction of oxidation or reduction occurring in anodic half or cathodic half of the cell. It could be oxidation or reduction.

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