What element's fusion stops in the core, triggering the final gravitational collapse?
Answer
Iron.
Fusion ceases when the core produces iron because fusing iron consumes energy rather than releasing it, removing the necessary outward thermal pressure to resist gravity.

Related Questions
What minimum initial mass is typically required for a star to end its life in a core-collapse supernova?Which stellar remnant forms if the progenitor star's initial mass was less than $8 M_
olm$?What quantum mechanical force first fails, initiating the gravitational collapse of the iron core?What mass range for the original star results in the formation of a neutron star?What is the primary quantum mechanical pressure that prevents a neutron star from collapsing further?If the mass of the collapsing core exceeds the neutron degeneracy limit (around $2$ to $3 M_
olm$), what object forms?What is the physical boundary surrounding a black hole's singularity from which nothing can escape?What element's fusion stops in the core, triggering the final gravitational collapse?How are many rapidly spinning neutron stars often detected after a supernova?What is the density state of matter at a black hole's singularity?