The terms theory and model are defined, and students learn how a theory remains valid. Atomic Theory: The Development of the Atomic Theory: The terms theory and model are defined, and students learn ...

Thank you for bringing to my attention the recent International Union of Pure & Applied Chemistry report “Atomic weights of the elements 2009” (C&EN, Dec. 20 ...

For the first time those little numbers that appear beneath some of the commonest elements in the periodic table boxes are about to change from a single value to an interval of numbers An ...

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, don't ...