When Epsom salt (magnesium sulfate) dissolves, it separates into its ions: a magnesium ion (Mg2+) and a sulfate ion (SO4 2-), which results in hard water. When hard water and soap are mixed, the magnesium ion reacts with soap molecules and forms a solid material called a precipitate, which does not dissolve.
The mass of an electron 1/1823 amu's = 0.0005 amu's... the average mass of litium is 6.941 amu's. by losing an electron, the mass of average atomic mass of the Lithium doesn't really change much.
