The periodic table is a well-organized chart that contains all the known elements in the universe. These elements are ...

And generations of children have sung the words, "hydrogen and helium, lithium, beryllium..." in an attempt to memorise some of the 118 elements. This year, the periodic table of chemical elements ...

The lightest element, hydrogen, has an atomic weight of 1.0078. The helium atom, next lightest in the table of elements, weighs 4.002. Are there no substances in between, with atomic weights of ...