Answer: Potassium
Explanation: Potassium is the chemical element with 19 electrons, 19 protons and 20 neutrons.
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Colligative
properties calculations are used for this type of problem. Calculations are as
follows:<span>
ΔT(freezing point) = (Kf)(molality)
ΔT(freezing point)
= 1.86 °C kg / mol (molality)
</span>Tf - 102.08 = 1.86m
Tf = 1.86m + 102.08
The concetration of the solution is needed in order to obtain a specific value.