chemistry revision

chemistry revision

1. Neils Bohr

   • Discovered Electrons orbit the Nucleus

2. James Chadwick

   • Discovered Existence of neutrons

3. Atoms of an element with different numbers of neutrons are called isotopes

   • He left gaps for elements that have not yet been invented

4. Nelson Mendeleev overcame some of the problems in the periodic table by leaving gaps in places and changing the order based on atomic weight