是否每種原子,都能被進行核裂變?

By nuclear fission, it means the breaking of a nuclues into two (or more) fragments.

The possibility of nuclear fission depends very much on the binding energy per nucleon. The binding energy per nucleon is highest for nucleus at atomic number 56, i.e. the element iron. Hence, nucleus with atomic number around 56 are stable. The distribution of binding energy per nucleon is given on the web-page below:

http://www.daviddarling.info/images/binding_energy.jpg

Fission produces more stable nuclei (i.e. higher binding energy per nucleon) from relatively unstable nucleus (i.e. with lower binding energy per nucleon). Hence, only nucleus with atomic number higher than that of iron could undergo fission. For nucleus with atomic number lower than iron could undergo fusion in order to form a more stable nucleus.

Hydrogen nucleus cannot undergo fission, but It can undergo fusion.

好似係mass number 56, 而非atomic number 56。