Different Kinds of Fission
When a few protons and neutrons come together they release some of the energy of the strong nuclear force. On the other hand, when a nucleus becomes too big it also becomes unstable. Uranium, the heaviest naturally occurring element, may emit a helium nucleus. That reduces the number of protons in the uranium nucleus to 90, which is an unstable form of thorium. The thorium also breaks up into lighter elements.
Big nuclei have a number of ways of breaking up. We have discussed the emission or breaking away of an electron, which turns a neutron into a proton. Above we just mentioned the emission of a helium nucleus. Another way of breaking up a nucleus is called electron capture. Normally a cloud of electrons surrounds a nucleus. The electrons form layers or shells. A uranium nucleus may capture one of the electrons from the innermost electron shell. The captured electron combines with a proton to make a neutron. That turns uranium into protactinium, an unstable element having a nucleus with 91 protons.
Eventually, through any of several series of unstable nuclei and various kinds of emissions or captures, uranium disintegrates into lead. Lead has 82 protons and 126 neutrons in its most abundant form. This form of lead is stable. Many alchemists have wished it were not stable. If lead lost three more protons and eight more neutrons it would become gold.
Big nuclei have a number of ways of breaking up. We have discussed the emission or breaking away of an electron, which turns a neutron into a proton. Above we just mentioned the emission of a helium nucleus. Another way of breaking up a nucleus is called electron capture. Normally a cloud of electrons surrounds a nucleus. The electrons form layers or shells. A uranium nucleus may capture one of the electrons from the innermost electron shell. The captured electron combines with a proton to make a neutron. That turns uranium into protactinium, an unstable element having a nucleus with 91 protons.
Eventually, through any of several series of unstable nuclei and various kinds of emissions or captures, uranium disintegrates into lead. Lead has 82 protons and 126 neutrons in its most abundant form. This form of lead is stable. Many alchemists have wished it were not stable. If lead lost three more protons and eight more neutrons it would become gold.
