Calculate the fraction of atom sites that are vacant for copper at its melting temperature of C (1357 K). Assume an energy for vacancy formation of 0.90 eV/atom

periodic trends is an atom that gets larger as the number of electronic shells increase, the radius of atoms increases as you go down a certain group in the periodic table of elements. in general, the size of an atom will decrease as you move from left to right of a certain period.

it's c (engineer's do their work with mechanical stuff not on any living being)