History of the Periodic Table Flashcards
1
Q
How were elements arranged in the early 1800s?
A
- By atomic mass
- By physical and chemical appearance
2
Q
What did Dmitri Mendeleev do to the periodic table?
A
- Left gaps in the table
- Predicted new elements
3
Q
Why were gaps left?
A
To make sure new elements with shared properties stayed in the same group
4
Q
What did the discovery of isotopes mean for Mendeleev?
A
That he was correct to not place elements in a strict order of atomic mass but to also think about physical properties
