dec 27, 1912 - Bohr Planetary Model a planetary model in which the negatively-charged electrons orbit a small, positively-charged nucleus. Was only accurate with only one electron elements (1913) Henry Moseley Made Moseley’s law, which states that the frequency of x-ray radiation has a mathematical relationship to an element's atomic number. (1913)
Added to timeline:
Date:
dec 27, 1912
Now
~ 112 years ago