An isotope of an element whose number of protons and neutrons place it on the edge of the Island of Stability is most likely

The composition of a nuclide (atomic nucleus) is defined by the number of protons Z and the number of neutrons N, which sum to mass number A.Proton number Z, also named the atomic number, determines the position of an element in the periodic table.The approximately 3300 known nuclides are commonly represented in a chart with Z and N for its axes and the half-life for radioactive decay

Explanation:

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.