atomic number 55

Thesaurus

Noun

1.atomic number 55 - a soft silver-white ductile metallic element (liquid at normal temperatures); the most electropositive and alkaline metalcaesium, cesium, Csmetal, metallic element - any of several chemical elements that are usually shiny solids that conduct heat or electricity and can be formed into sheets etc.cesium 137 - a radioactive isotope of cesium used in radiation therapypollucite - a rare mineral that is an important source of cesium