The simplest atom would arguable be hydrogen, containing just one proton and one electron. There are other hydrogen atoms, known as isotopes, all of which contain nuetrons.
Hydrogen 1 is known as protium, or normal hydrogen. H-2 is dueterium with one proton, one nuetron and one electron. H-3 is tritium. Any isotopes above H-3 are highly unstable and exist for fractions of a second.
432
29/50
yes
3/4
It is 8/17
10/7
7/9
7 over 4.
3/5ths
1 over 3
3 1/4
4 and 4/7ths