How does the criss cross method lead to a neutral zero charge ionic compound

An electron moved from shell n = 2 to shell n = 1. what most likely happened during the transition? a fraction of a photon was added. a photon of energy was absorbed. a fraction of a photon was removed. a photon of energy was released.

Measurements that have similar values are: a. usually accurate b. sometimes accurate c. always accurate d. never accurate

The organs inside the body and how they function together