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Hennig Brand periodic table theory
Hennig Brand was the first person recorded to have discovered a new element. Elements such as gold, silver, tin, copper, lead and mercury have been known since antiquity, the first scientific discovery of an element occurred in 1649 when he discovered phosphorous. -
Johann Dobereiner periodic table theory
Johann Dobereiner started to group elements with similar properties into groups of three or also known as triads.
1817- He noticed that the atomic weights of strontium, Sr, was halfway between the weights of calcium and barium. .
1829- He had discovered a halogen triad made up of chlorine, bromine, and iodine and an alkali metal triad of lithium, sodium and potassium. -
A.E.Beguyer de Chancourtois periodic table theory
A.E.Beguyer de Chancourtois was the first person to make use of atomic weights to reveal that the elements were arranged according to their atomic weight.
A.E.Beguyer de Chancourtois drew the elements as a continuous spiral around a cylinder divided into 16 parts and several sets of similar elements lined up, creating the first geometric representation of the periodic law. -
John Newlands periodic table theory
John Newlands was an english chemist, he roposed the Law of Octaves which stated that elements repeated their chemical properties every eighth element (octaves). -
Lothar Meyer periodic table theory
Lothar Meyer constructed an extended table and he classified elements not by atomic weight, but by valence alone. Lothar Meyer never came to the idea of predicting new elements and correcting atomic weights.The table was not published till 1870, a year after Mendeleev's table was published. -
William Ramsay periodic table theory
William Ramsay discovered the noble gases and realised that they represented a new group in the periodic table. -
Dmitri Ivanovich Mendeleev periodic table theory
Dmitri Ivanovich Mendeleev placed many elements out of order based on their atomic weights at the time and Dmitri Ivanovich Mendeleev predicted the existence and properties of unknown elements which he called eka-aluminum, eka-boron, and eka-silicon. Dmitri was the first scientist to make the periodic table like the one we have today, and this is the most significant date in the formation of the periodic table Dmitri helped Glenn Seaborg with his periodic table design. -
Ernest Rutherford periodic table theoty
Ernest Rutherford discovered the protons. This lead to the understanding that elements should be ordered in the periodic table by atomic number, not atomic weight. -
Henry Gwyn-Jeffreys Moseley periodic table theory
The first major revision of the entire periodic table was carried out by Henry Gwyn-Jeffreys Moseley, an English physicist who began his research under Ernest Rutherford.
1914- Moseley showed that each atomic nucleus could be assigned a number that was equal to the number of units of positive charge (was later identified as “protons”) associated with it. -
Glenn Seaborg periodic table theory
Glenn Seaborg co-discovered the transuranium elements, atomic numbers 94 to 102. The completion of the actinide series allowed Dmitri's design of the periodic table, this was then further developed by Glenn Seaborg with colour and a little bit of designing to make it look like the one we use today.
