Did you know that energy is not released in a continuous flow, but rather is released in “packets”? This discovery, known as quantum theory, changed the way we understand the basic properties of the atom. Many other advances in atomic theory were made in the 20th century, including the discovery of the neutron, which made the atom bomb possible.
The 20th century brought a major shift in our understanding of the atom, from the planetary model that Ernest Rutherford proposed to Niels Bohr’s application of quantum theory and waves to the behavior of electrons. With a focus on Bohr’s work, the developments explored in this module were based on the advancements of many scientists over time and laid the groundwork for future scientists to build upon further. The module also describes James Chadwick’s discovery of the neutron. Among other topics are anions, cations, and isotopes.
- anion = a negatively charged ion; an atom that has more electrons than protons
- cation = a positively charged ion; an atom that has more protons than electrons
- electronic = pertaining to electrons
- emit = give off; send forth
- spectrum (plural: spectra) = a continuing range such as of color or frequency; a series of colors arranged by wavelength as in a rainbow