History of the Periodic Table Flashcards
1
Q
What were the two ways to categorise elements?
A
1) their physical and chemical properties
2) their relative atomic mass
2
Q
What was Newlands’ Law of Octaves, why didn’t it work and why was it ignored?
A
He noticed that every 8th element had similar properties, but the pattern broke down on the third row (the transition metals). It was ignored as he didn’t leave any gaps.
3
Q
Why was his work criticised? (3 points)
A
1) his groups contained elements that didn’t have similar properties
2) he mixed up metals and non-metals
3) e didn’t leave gaps for undiscovered elements
4
Q
What did Dmitri Mendeleev do?
A
He put elements in order of atomic mass, and left gaps for undiscovered elements so that elements with similar properties could stay in the same groups.
