History of the Periodic Table

John Dobereiner was a German scientist who advanced the Law of Triads. Each feature was a group of three elements very much like each other. In 1829, he recorded bromine, an element that dropped about halfway between chlorine and iodine in atomic weight, also show halfway between them. Other “triads” that he identified were: calcium, strontium, and barium, and sulphur, selenium, and tellurium. Shortly, the boundary's were blurred, creating confusion, and these triads were treated like coincidences.

He anticipated that the second seven elements repeated the same possessions as the first seven closely, and he called them octaves (Rhythmic Interval). His law wasn’t taken too seriously, because the rest of the elements didn’t clearly follow it.

In 1864, he written The Modern Theory of Chemistry in which he published the use of atomic weights to group elements. In the work, he organized 28 elements into 6 families that had very much alike chemical and physical traits. His addition was the use of valance, or combining power of an atom of a specific element. He wasn’t as recognized as Mendeleev for his contribution because he didn’t leave gaps in his periodic table for the addition of elements.

Mendeleev had noticed that the periodic arrangement did not apply to heavier elements. He was driven to try to keep the arrangement by creating spaces for elements that weren’t found yet. The gaps he had attention on most were the gaps between aluminium and indium, silicon and tin, and born and yttrium. He called the unknown elements eka-aluminium, eka-silicon, and eka-boron, and had predicted the outcomes of their characteristics. He had written a paper where he demonstrated all known elements on a single periodic table. Like Meyer, he trained under Robert Bunsen and used similar techniques to complete the table

while Lord Rayleigh had been studying Nitrogen, he had established a gas that is much heavier that did not have a reaction to anything, and so he had called it Argon, which defines “Lazy one” and was one of the first inert element (gas that is low in reactivity).

William identified neon, krypton, and xenon with Lord Rayleigh in 1864. He also confined helium which had been recognized in the spectrum of the sun but had not been found on earth. He experimented with Nitrogen across liquid Magnesium which appeared to be in a small amount of unreactive gas that soon was known as Argon. In 1910 he made and defined radon.

In 1913 Henry had used X-ray to order the elements. Each element had a unique radiation pattern when X-rayed. He used this to show that atomic number because the atomic weight was most important in grouping and ordering the elements. The issue with Mendeleev's periodic table disappeared when atoms were positioned from lowest to highest atomic number.

Glenn was the creator of the concept of heavy elements. He sure how heavy elements that were rare in the earth fit in the periodic table. Both the Lanthanide series and the Actinide series are under the Aluminium column and have similar properties.