Periodic tables

Johann Döbereiner (1829): Döbereiner triads Döbereiner observed groups of three elements with similar properties, known as “triads.” He noticed that the middle element in each triad had properties that were an average of the other two . John Newlands (1864):  “Law of Octaves,” selements repeat their properties every eighth element when arranged by increasing atomic weight. Dmitri Mendeleev (1869): He arranged elements by increasing atomic weight and grouped them based on similar chemical properties. Mendeleev left gaps for undiscovered elements and predicted their properties with remarkable accuracy, like gallium and germanium. Henry Moseley (1913): Moseley resolved inconsistencies in Mendeleev’s table by arranging elements by atomic number (protons) rather than atomic weight, which refined the periodic law and led to the modern arrangement. Döbereiner triads इसकी खोज Dobereiner ने 1829 में की जन्म-1780, मृत्यु-1849 1829 में उन्होंने 3-group में तत्वों को रखा, जिसके गुण समान थे, जिसे उन्होंने Triad कहा। इसके […]