P3R1O1T1I1U1M3S1
12 points
PROTIUMS is validvalid
PROTIUM, an isotope of hydrogen [n]
PROTIUM, ordinary hydrogen of atomic weight 1, as distinct from deuterium and tritium [n]
PROTIUM, an isotope of hydrogen [n]
PROTIUM, ordinary hydrogen of atomic weight 1, as distinct from deuterium and tritium [n]