Putrid-Repeat t1_jcbh2oz wrote on March 15, 2023 at 5:21 PM

Reply to comment by caraamon in Radon is a monatomic gas, but its decay products are solids. After a decay, what happens to the individual atoms of the daughter elements? Do they stay suspended in the atmosphere or slowly rain out? by foodtower

Agreed with the others in that it is somewhat arbitrary as in the is no fixed number and it may vary with the element or molecule in question. But we usually consider it when the aggregate of atoms is relatively stable and has bulk properties of the solid. A gas or clump of atoms even of the same type likely will not behave as a solid of the same constituents.