1.1 The Early Periodic Table Flashcards
What did the scientists not knowing about the atoms cause?
It caused them to not be able to classify them in a table
How did some scientists classify the atoms in the 19th century?
Tried to classify them based on their properties and atomic weights
Why did scientists use atomic weights of elements to order them instead of the proton numbers?
They didn’t know the structure of the element so didn’t know about proton numbers
When did Newlands propose his law of octaves?
1863
What did scientists not know about atoms in the 19th century?
They didn’t know the structure of the atoms
What was Newlands law of octaves?
The law that stated that similar properties are repeated every eighth element
How did Newlands order the elements?
The 62 known elements at the time were arranged into 7 groups according to their atomic weights
After which element did Newlands law not work well?
Calcium
Why didn’t many people accept Newlands ideas?
After calcium, the elements properties didn’t match very well in the groups so other scientists didn’t accept his ideas
When did Mendeleev produce a better table?
1869
How did Mendeleev organise the elements?
He left gaps for the undiscovered elements so the groups of the known elements had similar properties
What did mendeleevs new table allow him to do?
Predict the outcome of the properties of the missing elements
What happened when the new elements were discovered?
Mendeleevs predictions were confirmed
Why did other scientists readily accept mendeleevs ideas?
His prediction were proven to be correct when the other elements were discovered
Who’s table became the basis for the modern periodic table?
Mendeleev
