The Periodic Table Flashcards
1
Q
What were elements originally ordered by
A
Atom weight or mass
2
Q
What did mandeleev do?
A
Arranged elements by atom weight, but he left gaps where he thought there were elements that weren’t discovered yet
3
Q
What are rows in the Periodic table called and what do they mean?
A
Periods, amount of shells
4
Q
How was mandeleev leaving gaps helpful?
A
It was easy to see that froups of elements had the same reactions and therefore it was possible to predict the properties and reaction of unkonw elements that weren’t even found yet
5
Q
What is an example of a predicted element?
A
Gallium
