What change occurs during the reaction: mno4- > mn2+? five electrons are lost. three electrons are lost. five electrons are gained. three electrons are gained.

Five electrons are gained.

Explanation:

Oxidation number or oxidation state of an atom in a chemical compound is  the number of electrons lost or gained. It is also defined as the degree of oxidation of the atom in the compound.

This is a theoretical number which can help to decipher the oxidation and reduction in a redox reaction.

Oxidation is the loss of electrons. The specie which is oxidized has has elevation in its oxidation state as compared in the reactant and the products.

The given reaction is shown below as:

Manganese in has oxidation state of +7

Manganese in has an oxidation state of +2

It reduces from +7 to +2 . It means that 5 electrons are gained.

i just calculated it all out, and not including weekends, and all the different days off. as of this school year (2018-2019) students are spending 2198 hours in school this year