A solid that forms and separates from a liquid mixture is a chemical change.
The process which has taken place is called CRYSTALLIZATION.
Generally, crystallization is the process by which solid crystals are precipitated from solution. Crystallization can also occur when a crystal melt or when a crystal get deposited directly from a gas, although these cases are rarer compare to crystals forming from solutions.
They are lost from valence shell (it's outermost shell of an atom).
->>> outside the atom
<span>Okay, a mole of potassium perchlorate contains 6.02x1023 formula units of potassium perchlorate, but you're asking about individual atoms. So, let's look at the formula: KClO3. That's 1 potassium, 1 chlorine, and 3 oxygens, for a total of 5 atoms per formula unit. Now, multiple 5 by Avogadro's number above, to get 30.1x1023, which simplifies to 3.01x1024 atoms.</span>
