On what number is the metric system based

The metric (or SI) system of units of measure is based on the number  10
and powers of it.

That's why people in Liberia, Burma, and the USA find it so confusing and
hard to learn, and why we stick to our familiar customary system based on
the number  3,  12,  1760,  5280,  16,  2,  4,  128, etc.

An  atom  (ours, not carroll's) consists of a positively charged  nucleus, surrounded by one or more negatively charged particles called  electrons. the positive charges equal the negative charges, so the atom has no overall charge; it is electrically neutral. most of an atom's mass is in its nucleus; the mass of an electron is only 1/1836 the mass of the lightest nucleus, that of hydrogen. although the nucleus is heavy, it is quite small compared with the overall size of an atom. the radius of a typical atom is around 0.1 to 0.25 nanometres (nm), whereas the radius of a nucleus is about 10-6  nm.  *  if an atom were enlarged to the size of the earth, its nucleus would be only 200 feet in diameter and could easily rest inside a small football stadium.read more on -