In this activity, we will pretend that nuts, washers and bolts are 3 kinds of elements. A single washer represents an atom of WASHER. A single nut represents an atom of NUT and a single bolt represents an atom of BOLT. Atoms can be put together to form compounds.
Certain naturally occurring radioactive isotopes are unstable: Their nucleus breaks apart, undergoing nuclear decay. ... All elements with 84 or more protons are unstable; they eventually undergo decay. Other isotopes with fewer protons in their nucleus are also radioactive.