The exemplary Carl Sagan, one of the world's most brilliant minds, says in his book Broca's Brain that there are 10,000,000,000,000,000 atoms in one grain of salt. That is to say there are ten million billion atoms in one microgram of sodium chloride.
If we could shrink ourselves into this crystalline world, he tells us, we would see rank upon rank of atoms in an ordered array, a regular alternating structure - sodium, chlorine, sodium, chlorine, specifying the sheet of atoms we are standing on and all the sheets above and below us.
A footnote informs us that chlorine (Cl) is a poisonous gas* deployed on battlefields during the first World War and that sodium (Na) is a corrosive metal which burns upon contact with water. Together they make NaCl, that is to say a placid and unpoisonous material, table salt.
*thankfully these days most of the world's countries have signed an agreement not to use poisonous gas or chemical weapons in war.