So atoms that have very low ionization energies. That basically means that electrons can be easily removed from those atoms. In other words, if we go to this table and we find atoms that have low ionization energies, for example, lithium lithium has 5.39 energy of ionization energy, while Fluorine, for example, has almost or has three times the value 17.42. That means that Lithium is much more prone to losing an electron than its fluorine. Same thing goes for sodium and same thing goes for chlorine. Chlorine has a higher value, higher ionization energy than sodium.