Your comment did inspire me to go looking for the distribution of elements within the iron core: "carbon, neon, oxygen, and silicon burning leave a core composed of iron, cobalt, nickel, and neighboring species, referred to as the iron-peak nuclei".

For anyone else interested in a readable article on a slightly more detailed look at supernova than wikipedia, and a discussion on the difficulties of modelling supernova, I liked this article: https://aip.scitation.org/doi/10.1063/1.4870009