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.

each chemical family is represented as a group or column on the periodic table. based on chemical properties, there are 6 types of chemical families. group 1 represents alkali metals, group 2 represents alkaline earth metals, groups 3 to 12 represent transition metals, groups 13 to 16 represent non-metals and other metals, group 17 represents halogens and group 18 represents noble gases.

it is b that is the answer.