about potassium

potassium has giant metallic structure. the attraction between metal ions and electron sea depends on charge density of ions. potassium ion is large, with only one possitive charge. charge density is small, so metallic bond is weak. less energy is required to be overcome in breaking of bond, so melting point is low. also, energy required to sideslip the atoms in cutting is lower, so potassium is soft.

Potassium (IPA: /pə(ʊ)ˈtasiəm/) is a chemical element. It has the symbol K (Latin: kalium) and atomic number 19. The name "potassium" comes from the word "potash&;quot;, as potassium was first isolated from potash. Potassium is a soft silvery-white metallic alkali metal that occurs naturally bound to other elements in seawater and many minerals. It oxidizes rapidly in air and is very reactive, especially towards water. In many respects, potassium and sodium are chemically similar, although organisms in general, and animal cells in particular, treat them very differently.

Potassium has density 0.87, so it's soft.

The melting point and boiling point of potassium at 1 atm. are 63.2.degree. C. and 757.degree. C. respectively.

it's non-sense to say it's high or low without comparing with other elements....