Answer:
false, Potassium and fluorine are not halogens.
only fluorine here is halogen.
potassium is an alkali earth metal it doesn't comes under category of halogens, but fluorine
is a non metal which comes under halogen family.
Quantity of K2S m = 0.105 m
Number of ions i = 2(K) + 1(S) = 3
Freezing point depression constant of water Kf = 1.86
delta T = i x m x Kf = 3 x 0.105 x 1.86 = 0.586
Freezing point = 0 - 0.586 = 0.586 C
Boiling point constant of water Kb = 0.512
delta T = i x m x Kb = 3 x 0.105 x 0.512 = 0.161
Boiling point = 100 + 0.161 = 100.161 C
In the most common isotope of fluorine, fluorine-19, it has 19 electrons, 9 protons and 10 neutrons. Hope this helps you! Good luck!!