Now more than one electron can be pulled off. For example, calcium. Calcium in its neutral state, can take away two electrons to become calcium plus two. So that means some atoms can pull away or can give off more than one electron. Now, the energy required to pull away that first electron is known as The First ionization energy, while the energy Required to pull away that second electron is Known as A second ionization energy and So on. Now let's look at the following now, the less likely an atom gives up the electron, the more energy is required to pull that electron off.