Mad as a hatter

predicted electron configurations for transition elements and the lanthanide and actanides are often wrong, zirconium is 1s2, 2s2, 2p6, 3s2, 3p6, 4s2, 3d10, 4p6, 5s2 or [Kr] 4s2, 3d10, 4p6, 5s2 and holmium is 1s2, 2s2, 2p6, 3s2, 3p6, 4s2, 3d10, 4p6, 4d10, 5s2, 5p6, 4f11, 6s2 or [Xe] 4f11 6s2

well you don't remove atoms you add or remove protons, the stuff that defines which element it is and yes it is possible, it's how new elements are made, the machines are particle accelerators which bombard elements with protons/neutrons/atoms at other atoms and boom new element

just carefully pour some water over the KOH and mix carefully, reaction is exothermic

yes of course they're radioactive, for example uranyl nitrate (UO2(NO3)2) is a salt of uranium, both are radioactive

well you could make sodium without electrolysis by using magnesium and sodium hydroxide with a menthol catalyst 2Mg + 2NaOH ----Menthol, 200C--> 2MgO + 2 Na + H2 to make sure nothing explodes keep apparatus airtight and use mineral oil as a solvent ig, also keep bubbler for H2 and don't use water because it'll probably backflow