23h 42min, dec 31, 1924 y - Quantum Mechanical Model (1926)
Description:
The quantum mechanical model of the atom uses complex shapes of orbitals (sometimes called electron clouds), volumes of space in which there is likely to be an electron. So, this model is based on probability rather than certainty.Added to timeline:
Date:
23h 42min, dec 31, 1924 y
Now
~ 100 years ago