Atomic Models and Subatomic Particles

Vocabulary flashcards covering Thomson's and Bohr's atomic models, as well as the fundamental subatomic particles.

Plum Pudding Model

An atomic model described by J.J. Thomson in the late 1890s, where negative electric charges (electrons) are represented as plums in a shapeless mass of uniform positive electrification (pudding).

Cathode Rays

Physical streams investigated by J.J. Thomson in the late 1890s, leading to the conclusion that electrons are an integral part of all atoms.

Bohr's Atom

An atomic model proposed by Niels Bohr in 1913 resembling a miniature solar system, where negatively charged electrons revolve around a small, dense, positively charged nucleus in fixed, well-defined orbits or energy levels.

Nucleus

A positively charged region at the center of an atom consisting of protons and neutrons packed tightly together.

Nucleons

The collective term for the two subatomic particles (protons and neutrons) packed tightly together in the nucleus.

Proton

A subatomic particle carrying one unit of positive electric charge with a mass of $1.00728\,amu$.

Neutron

A neutrally charged subatomic particle with a mass of $1.00867\,amu$.

Electron

A very small subatomic particle found outside the nucleus carrying one unit of negative electric charge with a mass of $0.000549\,amu$.

Electron Shells

Specific regions outside the nucleus in which electrons exist, representing different electron binding energies or energy levels.