Development Of The Periodic Table Flashcards
Approximately how many elements are in the modern periodic table?
100
How were elements ordered in the first list of elements?
By atomic mass
Were there gaps in the first list of elements?
No
How were elements grouped in the first list of elements?
Not grouped
How were metals and non-metals separated in the first list of elements?
No clear distinction
What were problems with the first list of elements?
Some elements grouped inappropriately
How were elements ordered in Mendeleev’s Periodic Table?
Normally by atomic mass but some elements were swapped around
Were there gaps in Mendeleev’s Periodic Table?
Gaps left for undiscovered elements
How were elements grouped in Mendeleev’s Periodic Table?
Grouped by chemical properties
How were metals and non-metals distinguished in Mendeleev’s Periodic Table?
No clear distinction
What were problems with Mendeleev’s Periodic Table?
Incomplete, with no explanation why some elements had to be swapped to fit in the appropriate groups.
How are elements ordered in the modern periodic table?
By atomic number
Are there gaps in the modern periodic table?
No gaps - all elements up to a certain atomic number have been discovered.
How are elements grouped in the modern periodic table?
By the number of electrons in the outer shell
How are metals and non-metals distinguished between in the modern periodic table?
Metals to the left, non-metals to the right
