How to figure out if an equation is exothermic or endothermic?

Exothermic is exterior  or the outside of the something or item.

Endothermic is inside or the interior of the obeject in which you are using.

sodium (na), for example, has one electron in its valence shell. this is an unstable state because that valence shell needs eight electrons to be full. in order to fill its valence shell, find a way to add seven electrons to its valence shell