“How can we measure the amount of energy needed to remove an electron from an atom?”
From common knowledge, we know that if we want to remove an object, it would require energy. So it would logically follow that if we would want to remove an electron from the orbit of an atom, it would require energy as well. Now since atoms come in a diffuse number of sizes as a result of the different combinations of protons and electrons, how can we find a pattern to quantify which elements require more energy to remove an electron? Well, let’s think about it. As mentioned earlier, each atom will come in a different number of sizes. Furthermore, it can be observed that the larger the size, the more decrepit the hold of the nucleus will be on the orbiting electrons. From this reasoning, we can deduce that the larger the radius, the smaller amount of energy would be required to take an electron. This phenomena is termed Ionization energy, and to observe the pattern for ionization energy, one simply has to remember that since ionization energy is inverse to the size of an element, the further up and right one goes on the periodic table, the stronger the hold of the nucleus on the electrons will be. As a result, elements on the left side of the periodic table tend to be better oxidizers since it does not take too much energy to ionize them, while the opposite is true for elements further to the right side of the periodic table.