Releasing Energy from Processes: Electrons & Ions

[physicsman2]

Homework Statement

Which of the following processes release energy to the surroundings?
-Removing an electron from a neutral atom
-Separating a sodium ion (Na+) from a chloride ion (Cl-)
-Removing an electron from a positively charged ion
-Elevation of an electron from a lower energy level to a higher energy level within the same neutral atom
-Adding an electron to a neutral halogen atom

Homework Equations

The Attempt at a Solution

i have no idea but why is it the last one, i can't understand why adding an electron to a neutral halogen atom will release energy to the surroundings

 

[windwitch]

Try relating the stability of a molecule to the amount of potential energy it has when adding an electron to an already stable molecule.