Elements are arranged in the periodic table in order of increasing atomic number. For example hydrogen has the atomic number of one, helium two, lithium three etc. The first energy level (the one ...

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 ...

Photo: Niels Bohr's research notes for his new atomic theory Rutherford's find came from a very strange experience. Everyone at that time imagined the atom as a "plum pudding." That is ...