Can someone check if what i wrote so far makes sense and if i made a mistake.

I don't really know what it's about but everything looks okay to me. There might be some mistakes on the last sentence but i'm not completely sure.

It looks great, except, I would rewrite the first sentence as "Everett knew it was dangerous to be within close proximity to a cheetah". Also, in the second sentence, I would get rid of the words "at the moment". They aren't really necessary. That's all. Everything else looks perfect. Good job introducing the subject, by the way.

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 -