The History Of The Periodic Table Flashcards
When did John Dalton develop his atomic theory?
1800s
Name three things John Dalton did to help develop his atomic theory.
Calculated some atomic weights, did experiments and invented symbols for atoms and molecules.
What were John Dalton’s most important conclusions?
- all matter is made of atoms
- atoms cannot be broken down into anything simpler
- atoms are rearranged in a chemical reaction
- all the atoms of a particular element are identical to each other and different from the atoms of other elements
- compounds are formed when two or more different kinds of atoms join together
When did John Newlands put forward his law of octaves?
1864
How did John Newlands develop the law of octaves?
He arranged all the elements known at the time into a table in order of relative atomic mass. When he did this, he found that each element was similar to the element eight places further on.
After arranging the elements into a table in order of relative atomic mass, what did Newlands find?
He found that each element was similar to the element eight places further on.
Who created the law of octaves?
John Newlands
When did Mendeleev publish his periodic table?
1869
How did Mendeleev start to develop his periodic table?
He arranged the elements known at the time in order of relative atomic mass, but he did some other things that Newlands didn’t that made his table much more successful.
How was Mendeleev’s periodic table more successful than previous versions?
He realised that the physical and chemical properties of elements were related to their atomic mass in a ‘periodic’ way, and arranged them so that groups of elements with similar properties fell into vertical columns in his table.
