As the core of a star that is 1.4 or more times as massive as the Sun begins to yield to gravity and starts to shrink, it grows hotter and denser, and a new series of nuclear reactions begins, temporarily halting it's collapse. When the core becomes essentially just iron, fusion ceases, and, in less than a second, the star begins gravitational collapse, the core temperature rises to over 100 billion degrees, and the iron atoms are crushed together. The repulsive force between the nuclei overcomes the force of gravity, and the core recoils out from the heart of the star in an explosive shock wave called a .

plasma - state of matter made up of electrically charged particles

the seeing the electronic configuration we can say that the element is fluorine.

fluorine is the most electronegative element in the periodic table.

but by only seeing the configuration we cannot say about its reactivity because we don't know if its configuration after excitation or by addition of electrons.

but if not then, it is the lightest halogen and exists as a highly toxic pale yellow diatomic gas at standard conditions. as the most electronegative element, it is extremely reactive: almost all other elements, including some noble gases, form compounds with fluorine.