Attempted to created a Philosopher’s Stone He heated residues from boiled urine, and a liquid dropped out and burst into flames
Hydrogen was observed and collected long before it was recognised as a unique gas by Robert Boyle in 1671, who dissolved iron in diluted hydrochloric acid.
it was first recognized as an element in the second half of the 18th century.
first modern textbook about chemistry. It contained a list of "simple substances" that Lavoisier believed could not be broken down further, which included oxygen, nitrogen, hydrogen, phosphorus, mercury, zinc and sulfur, which formed the basis for the modern list of elements
Scientists began to see patterns in the characteristics.
formulating one of the earliest attempts to classify the elements.
vis tellurique' (telluric screw), a three-dimensional arrangement of the elements constituting an early form of the periodic classification
56 elements into 11 groups, based on characteristics.
produced several Periodic Tables. His first table contained just 28 elements, organised by how many other atoms they can combine with. Unfortunately for Meyer, his work wasn’t published until 1870, a year after Mendeleev’s periodic table had been published. He was the first person to recognise the periodic trends in the properties of elements, and the graph shows the pattern he saw in the atomic volume of an element plotted against its atomic weight.
Discovery started the development of the periodic table, arranging chemical elements by atomic mass. He did so by writing the properties of the elements on pieces of card and arranging and rearranging them until he realised that, by putting them in order of increasing atomic weight, certain types of element regularly occurred. He predicted the discovery of other elements, and left spaces open in his periodic table for them.
three types of radiation; alpha, beta and gamma rays
Noble gases added to the periodic table as group 0.
electrons orbit the nucleus of an atom
electrons move around a nucleus in discrete energy called orbitals. Radiation is emitted during movement from one orbital to another.
identified protons in the atomic nucleus.
provided atomic numbers, based on the number of electrons in an atom, rather than based on atomic mass.
first discovered neutrons, and isotopes were identified, this was the complete basis for the periodic table
first split an atom by bombarding lithium in a particle accelerator, changing it to two helium nuclei.
identified lanthanides and actinides (atomic number >92), which are usually placed below the periodic table.