1863
John Newlands was an English chemist that produced a series of papers from 1863 to 1866 that noted his discovery that was about how every eighth interval of the elements ordered in order of their atomic weight on their current periodic table had similar chemical properties. He compared this discovery to the music, due to the number of intervals being eight, just like an octave. This was the beginning of the grouping of the elements in the periodic table. 1869 With approximately 60 elements known to scientists at the time, Dimitri Mendeleev was a Russian chemist that started the first proper development and organisation of the periodic table, with some believing it took him years of hard work, others believing that the idea came to him in a dream. He arranged the known elements by their atomic mass, and predicted the mass of other elements that were left to be discovered and left spaces in his periodic table for them on discovery. Because of this, Mendeleev’s was once of the most accurate periodic table for decades. 1886 Antoine Bequerel was a French physicist who first discovered radioactivity in its basic form. He discovered that the particles in radiation were negatively charged, which produced more energy but was also harmful. His discoveries gave way for other scientists like Marie and Pierre Curie – who discovered more radioactive elements in the couple of decades after his discovery – who furthered his work and bettered the current understanding of this new and very dangerous type of element. 1894 William Ramsay was a Scottish chemist who founded the grouping of the noble gases on the periodic table, as well as discovering half of the elements that are in that group of inert gases. He first discovered argon when he and a colleague isolated all known gases from the air and were left with that single identifiable element. His next major discovery was helium, and then following similar procedures he used to find argon, Ramsay later discovered neon, krypton, and xenon. 1913 The periodic table had been around for some decades at the time, but it contained many flaws regarding its ordering system and layout, which made scientists very annoyed as new elements were being discovered every year and the old layout of the periodic table was becoming more and more problematic. This is when Henry Mosely – the English chemist – discovered that the flaws in the periodic table system were basically non-existent when the elements were ordered by their number of protons (which was later called their atomic number), rather than their atomic weights, which were often very precise decimals that were difficult to order. 1913 Neils Bohr was a Danish physicist that is most well-known for his creation of “The Bohr Model,” which was the most accurate model showing the setup of atoms ever made, which laid the foundation for scientists – even in this current day – to make even more advanced discoveries that would’ve been discovered significantly later if not for his progressive research. He discovered that the electrons and nucleus’ travelled in different orbits, and that the number of electrons determined some chemical properties for the particular element. And due to his work being one of the most contributing discoveries to science, the element Bohrium (number 117 on the periodic table) was named in his honour. |