Question: how big is atom

Thomas Booth answered on 22 Jun 2017:

The exact size of an atom depends on the element (Helium is the smallest!). Google tells me they are 1×10^-8 cm. Which is 0.00000001 cm. That doesn’t really mean anything but to put it into some sort of scale I remember hearing that if you put an atom side by side for every human being on the planet the string would only reach 1m in length!