Development of the periodic table (AQA GCSE Chemistry): Flashcards
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What 19th century scientists knew about elements
What 19th century scientists knew about elements
Properties of elements and atomic weight
What 19th century scientists didn't know
What 19th century scientists didn't know
Protons, neutrons, electrons, and atomic numbers
How early scientists organized elements
How early scientists organized elements
By atomic weight
Number of columns in first periodic table
Number of columns in first periodic table
Seven
When first periodic table pattern broke down
When first periodic table pattern broke down
After calcium
Problem with early periodic table and new elements
Problem with early periodic table and new elements
No space left for new elements to be discovered
Year Mendeleev published his periodic table
Year Mendeleev published his periodic table
1869
Mendeleev's key innovation in his table
Mendeleev's key innovation in his table
Left gaps for undiscovered elements
Example of Mendeleev swapping elements
Example of Mendeleev swapping elements
Iodine before tellurium (despite higher atomic mass)
What Mendeleev predicted about gaps
What Mendeleev predicted about gaps
Properties of elements that would fill the gaps
Result when missing elements were discovered
Result when missing elements were discovered
Properties matched predictions almost exactly
Why it's called the 'periodic' table
Why it's called the 'periodic' table
Similar properties appear at regular intervals