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Johann Dobereiner
the beginning of the periodic table was john who grouped elements based on similatities. -
time to organize
by new organisation was necessary as abut 60 elements were recognised -
first periodic table
The first periodic table was made by alexandre begyer de chan courtois -
New system
john newland wanted to update the system so he put 62 elements in order of increasing atomic mass -
mendeleev's idea
dimitri mendeleev decided to arrange the elements by atomic weight. It had 17 coulumns, 2 partial periods with 7 elements in each followed by 2 almost complete periods -
review of table
mendeleevs recised table -
inertgases
In 1895 william ramsey and lord rayleigh discovered and in 1904, they were inert gases awarded the nobel prize. -
the proton
Mosely discovered the proton and arranged elements in increasing atomic numbers and not masses. our modern periodic table is based on this -
law of triads
law of triads was suggested do dobereiner. He said that the middle element had atomic weight which was the average of the other 2 elements -
transuranium elements
Glenn Seaborg discovered transuranium elements 94 to 102 and resahped the periodic table by putting the lanthanide/ actinide series at the bottom in 1951 seasory got the nobel prize
