There is enough iron in the Sun for an iron core. Nevertheless, the standard model of the Sun supposes that, because of the very high temperature, the interior

There is enough iron in the Sun for an iron core. Nevertheless, the standard model of the Sun supposes that, because of the very high temperature, the interior of the Sun remains mixed well enough so that the heavy elements like iron cannot segregate to form a distinct core, but only, as you have mentioned for helium, the concentration of heavy elements is somewhat higher in the center than at the surface. However the standard model of the Sun is not very certain, because the behavior of matter at extremely high pressures and temperatures is not known well enough.