Sylvite is separated from halite by dissolution or flotation and crystallized as KCl. Metallic K comes from reducing molten KCl with Na vapor at ~870 °C — K is more volatile, so it distills off (a Le Chatelier trick).
Research Elements K · atomic number 19 Alkali metal · period 4, group 1 [Ar] 4s1 Shells: 2, 8, 8, 1 Valence electrons: 1 in the outer shell (4s1) Green dots are the outer shell's s and p electrons. Softer green dots are the d electrons of transition metals, and the d and f electrons of lanthanides and actinides: they often take part in bonding, but not always. Grey dots are the core. Ground-state configuration from the NIST Atomic Spectra Database (A. Kramida, Yu. Ralchenko, J. Reader and the NIST ASD Team). Abundance is the mole fraction of the element found as that isotope on Earth; digits in parentheses are the uncertainty in the last digits. Masses and abundances from NIST, Atomic Weights and Isotopic Compositions (J. S. Coursey, D. J. Schwab, J. J. Tsai and R. A. Dragoset, National Institute of Standards and Technology).Potassium
Electrons
How it's obtained
Natural isotopes
Isotope Relative atomic mass Abundance 39K 38.9637064864(49) 0.932581(44) 40K 39.963998166(60) 0.000117(1) 41K 40.9618252579(41) 0.067302(44)