How do the odd proton-number elements originate?

I have a question about the origin of the odd proton-number elements in the periodic table, please.


As it is generally thought that the big bang produces hydrogen first, and then hydrogen combined to form helium. Helium combines into beryllium, and beryllium into carbon, etc... This means that all fusion atoms have even numbers of protons, does not not?


Then, if radioactive decay involving protons always result in a 2 protons decay, how then can we ever end up with atoms of odd number of protons, such as lithium, boron, nitrogen, etc?




One of the most significant sources of an odd-numbered element is the [CNO cycle](https://en.wikipedia.org/wiki/CNO_cycle) that operates to a minor extent in our Sun and more prominently in more massive stars like Sirius. There are actually several CNO cycles, but they all involve carbon, nitrogen and oxygen interchanging through the absorption of protons and the emission of alpha and positron beta particles. The net result is the same as direct hydrogen-to-helium fusion: four protons absorbed into the nuclei during this cycle are converted into one alpha particle and two positrons that are emitted, plus the same energy that we see with the direct fusion. This mechanism is responsible for nitrogen being the second most abundant odd-numbered element in the Universe, behind hydrogen but beating lithium and boron despite the lower atomic numbers of the latter two elements.


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