(A) If 15.0 mL of 8.28 x 10^-4 M Pb(CH3COO)2 are added to 12.0 mL of 5.00 x 10^-5 M NH4Br, will solid PbBr2 (Ksp = 6.3 x 10^-6) precipitate?
(B) If a precipitate will not form, what bromide ion concentration will cause a precipitate of lead bromide to form?
(C) If a precipitate will form, what is the minimum [Br-] that could have been present without initiating precipitation? Assume the total volume used in the above example.

first one is the correct answer

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.