Periodic table Development Flashcards
What was newlands theory called
Law of Octaves
When was newlands theory put forward
1864
How were elements arranged in his periodic table
I’m order of relative atomic mass
What did newland find when he arranged the elements
He found a pattern showed each element was similar to the element 8 placed ahead of it
What did newlands table show
A repeating or periodic pattern of properties. But this pattern eventually broke down
What did newlands have to do because of how he ordered the elements
By ordering strictly by atomic mass. Newlands was forced to put some elements into groups
What did this mean for the table
It meant his table was not accepted by other scientists
When did Mendeleev publish his table
1869
How did Mendeleev arrange the elements in his table
He arranged the elements known at the time in order of relative atomic mass
What did Mendeleev do that made his table more successful
He realized that the physical and chemical properties of elements were related to their atomic mass in a repeating way.
He arranged them so that the groups of elements with similar properties fell into vertical columns in his table.
What did Mendeleevs method of arranging elements mean
It meant that there were gaps in his horizontal rows or ‘peroids’
How did Mendeleev see this
Instead of seeing this as a problem Mendeleev though it simply meant that the elements which belonged in the gaps had not yet been discovered.
What could Mendeleev work out from these gaps
He was able to work out the atomic mass of the missing elements and predict their properties
