1 Periodic Table - Summary.pdf

periodic table periodic table The modern periodic table is a list of John Newlands - elements arranged in increasing atomic weights.He found that the eighth element number. had properties similar to the first. He called It is arranged into horizontal periods & these groups octaves. vertical groups s...

periodic table periodic table The modern periodic table is a list of John Newlands - elements arranged in increasing atomic weights.He found that the eighth element number. had properties similar to the first. He called It is arranged into horizontal periods & these groups octaves. vertical groups scientists: increasing atomic Dmitri Mendeleev - He arranged the elements in order of increasing atomic weight. Ancient Greeks - Stated there were 4 Listed in subgroups elements such as elements: Earth, Air, Water, Fire. Cu & Ag whose properties did not fit into the main group. Robert Boyle - Element cannot be split up into simpler substances by chemical means. Put Iodine & Tellurium out of order of Atomic weight. Humphry Davy - Used electrolysis to break down water into hydrogen and oxygen. Isolated potassium and sodium. Johann Dobereiner - Triads. The elements in a triad has similar chemical properties. The atomic weight of the middle element is half way between the other 2 elements. Left gaps for undiscovered elements Predicted the properties of these yet to be discovered elements. Henry Moseley - Arranged by atomic number, not atomic weight. He used X-rays to determine the number of protons in the nucleus of an atom.