4. Scientists continued to make discoveries about elements long after Mendeleev first produced his table. Explain how later discoveries provided evidence to support Mendeleevs organisation of the elements.
Answer (1)
Discovery of New Elements – Scientists discovered elements like gallium and germanium after Mendeleev predicted their existence and properties. These elements matched his predictions closely, proving his arrangement was accurate.Atomic Number – In the early 1900s, Henry Moseley showed that elements are better arranged by atomic number (number of protons), not atomic mass. This confirmed the pattern Mendeleev observed and corrected a few inconsistencies in his table.Noble Gases – The discovery of noble gases filled in gaps in the periodic table and fit well into Mendeleev’s structure, supporting the idea of repeating patterns (periodicity).
