jul 5, 1913 - 1913- Niels Bohr
Description:
PLANETARY MODELNiels proposed a model where the atom was a small and positively charged nucleus surrounded by electrons. He discovered that electrons travel in separate groups and found that the number of electrons in an outer shell can determine the type of element.
Added to timeline:
Date:
jul 5, 1913
Now
~ 112 years ago