The Develepment Of The Periodic Table Flashcards
How are the elements are arranged today.?
The elements are arranged by their atomic number.
Before the discovery of protons neutrons and electrons how were the elements in the periodic table arranged?
The elements were ordered by their atomic weights.
How did Mandaleev overcome each problem?
He changed the order based on atomic weights and left gaps for undiscovered elements.
What happened for scientists to finally believe in Mandaleevs theory?
Mandaleeves table was widely excepted as he predicted elements where he left gaps and often was correct.
What discovery lead to the understanding of how the elements were originally arranged was not always correct?
Knowledge of isotopes made it possible to explain why the order based on atomic weights was not always correct.
What were the problems with the early models of the periodic table?
The early periodic tables were incomplete and some elements were placed in inappropriate groups if the strict order of atomic weights was followed.
