Everything in the world is made from about 100 different chemical elements that join together in different ways to form all the solids, liquids and gases we see around us. All of the elements have ...

The questions in this quiz are suitable for GCSE chemistry students studying early ideas about atoms, the structure of the atom, atomic number and mass number. If you struggled with the quiz ...

and atomic radius. Many scientists worked on the problem of organizing the elements, but Dmitri Mendeleev published his first version of the periodic table in 1869, and is most often credited as its ...

Even though emeralds and rubies are very different colors, they both have the same secret ingredient in their atomic ...