This left enough radioactive residue in their mouths to cause cell damage ... of a gram of radium that the Curies eventually extracted. It's classified in the periodic table as an alkaline earth metal ...

For each alpha particle a radioactive sample emits ... What's more, to the surprise of most chemists and going against the well-known trends of the periodic table, it turns out that francium is not ...

Stable isotopes are non-radioactive forms of atoms ... Eighty out of the first 82 elements in the periodic table have stable isotopes. Measuring and analysing their distribution allows for many ...