Short answers, pulled from the story.
Humphry Davy isolated potassium in 1807 using a newly invented voltaic pile. He derived the element through electrolysis of molten caustic potash. This process created potassium, which is the first metal ever isolated through electrolysis.
Naturally occurring potassium contains three isotopes with ninety-three point three percent being stable potassium-39. Six point seven percent exists as radioactive potassium-40 with a half-life of billions of years. The decay of this isotope results in higher concentrations of argon in the atmosphere over time.
A healthy human body contains approximately twelve hundred grams of total potassium distributed throughout tissues. Ninety-eight percent of this potassium resides inside individual cells rather than plasma. Plasma levels stay tightly controlled between three point five and five point five millimoles per liter.
Canada leads world potash production with deposits lying below surface in Saskatchewan province. Deposits span from Great Britain over Germany into Poland within the Zechstein layer. About ninety percent of global supply arrives as potassium chloride known simply as MOP.
Lethal injection executions utilize potassium chloride specifically for its ability to stop heart rhythm quickly. Overdose leads to hyperkalemia causing fatal brady- and tachy-arrhythmias rapidly. Studies show that severe deficiency eventually causes death if withholding continues beyond one week duration.