answer:Many elements do. The energy required to remove a single electron from the highest occupied energy level is called the first ionization energy. The energy needed to remove a second electron from the same atom, after the first one has already been removed, is called the second ionization energy. Look at the removal of two electrons from a calcium (Ca) atom: Ca + energy = Ca+ + e- This equation represents the 1st ionization energy. Ca + energy = Ca2+ + e- This equation represents the 2nd ionization energy. The second electron to be removed from the nucleus is more tightly bound. This is because of a greater electrostatic attraction to the positively charged nucleus. Therefore, it takes more energy to remove this electron. The second ionization energy is always higher than the first. Measuring the atomic radii of the elements correlates with the ionization energies. As you go across a row of the periodic table, the atomic radius of each element becomes smaller. Consider this in light of the ionization energies. Moving from left to right across a row in the periodic table, the ionization energies increase. The nuclear charge (the number of protons) is increasing so the electrons are held more tightly. Does that clear a few things up?