With atomic number 88, it has four natural isotopes of atomic weight 228, 226, 224 and 223 - though there are a remarkable 21 more artificial isotopes. A later starring role for radium would be as the ...

There are 118 elements in the periodic table, each with a unique symbol and atomic number. Symbol: A one or two-letter abbreviation used to represent the element. Atomic number: The number of ...