The Periodic Line – with Iron in the middle
Iron, that large ball of hot stuff you are living on, and iron that large ball of hot stuff that makes you live, is the measure of all things. It should be placed firmly in the middle of a “periodic line” to help teach nuclear physics. Rather than be thrown somewhere inside a confusing periodic table, used to teach chemistry.
Because you have to add energy to “fuse” all of the elements up to iron, and you have to take energy away in order to, urr, “fission” all elements after iron.
So from a nuclear perspective, iron is central. It is the most stable element and is least willing to be synthesised into other elements. After all, given the right amount of energy, if the other elements could slide up or fall back to iron, they probably would. Maybe 😉