Question

the gain of electrons is called blank. when a substance gains electrons, the oxidation state select an answer. the options for the oxidation state change are: goes up (increases), goes down (decreases), changes in an unpredictable direction

Explanation:

In chemistry (a subfield of Natural Science), the gain of electrons is called reduction. When a substance gains electrons, its oxidation state decreases because each electron has a negative charge, so adding electrons reduces the overall positive charge (or increases negative charge) of the substance's atoms. So for the oxidation state change, it goes down (decreases).

Answer:

The gain of electrons is called reduction. For the oxidation state: goes down (decreases)