In chemistry, Coulomb’s law relates the energy to the distance of electrons from the nucleus of an atom, and the charges present from the charged particles. The relationship is inverse, meaning the further away from the nucleus, the less energy it takes to remove an electron. The charge is also pertinent, as it impacts the equation supporting Coulumb’s law (E= charge/distance). Unlike energy and distance, energy and charge are directly related.
Similar to chemical bonds, the removal of an electron requires activation energy to overcome the attractive forces between the positive and negative charged particles. This makes the process endothermic, instead of exothermic. The amount of energy required to move an electron is dependent on how the electrons are organized within an atom. For example, if an atom is buffered, or shielded, by two electrons in a lower orbital, the atom will experience less less positive charge because it is further away from the nucleus. The other electrons absorb most of the positive force exerted by protons in the nucleus, making it easier to remove.
The energy required to remove an electron is much larger than that needed to excite an electron. Electron excitement simply moves the electron up a shell level, while electron removal takes it completely out of the atom, which is much more difficult to do.