The Periodic Table
* The first model was created by Mendeleev.
* 90 elements are nature made.
*Tectnitium was the first artificially made element.
* The columns are called groups.
* The periodic table includes metals, non-metals, and metalloids.
* Out of the three, metals are greatest in number.
* The rows are called periods.
* The most recent version was approved in 2010.
* An element's period number is the highest unexcited energy level for an electron of the element.
* The current model has 118 elements.
Timeline(bottom to top)
JJ Thomson and his model.William Crookes and his modelFrancis Ashton and his invention: the Mass spectrograph |
Five Scientists that made a contribution to our current understanding of the atom:
Democritus
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