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Antoine Lavoisier
Lavoisier was the first person to attempt to group the elements based on their properties, grouping them into gases, non-metals, metals and earths. He also proposed that water was a compound and that hydrogen, oxygen, carbon etc. were elements. -
John Newlands
Newlands was the first person to arrange elements into a table based on their atomic mass. He discovered that every 8 elements had similar properties and called it the law of octaves. He made 8 groups of 8 elements into the table but didn't leave gaps for undiscovered elements. -
Dmitri Mendeleev
Mendeleev is widely known as one of the greatest contributors to the periodic table we use and study today. He also invented the Periodic Law. -
Henry Moseley
Instead of using atomic mass, Moseley used atomic numbers of elements to arrange a periodic table of elements. He discovered that he could identify elements based on how many protons they had, further building upon Mendeleev's table.