Development of Atomic Model

This set of flashcards covers essential vocabulary and concepts from the lecture notes on the development of atomic theory and radioactivity.

Democritus

Proposed that matter is made up of tiny, indivisible particles called atoms.

John Dalton

Formulated the atomic theory that elements are composed of atoms, which are indivisible and differ in mass.

Thompson's Discovery

Discovered electrons and proposed the 'plum pudding model' where electrons are embedded in a positive charge.

Rutherford Scattering Experiment

Demonstrated that atoms have a dense nucleus containing protons, with electrons orbiting outside.

Nuclear Model of the Atom

Proposed by Rutherford, detailing that atoms consist of a nucleus and a cloud of electrons.

Bohr Model

Introduced the concept of energy levels or shells where electrons orbit the nucleus.

Protons

Positively charged particles found in the nucleus of an atom.

Neutrons

Neutral particles found in the nucleus, contributing to atomic mass without affecting charge.

Isotopes

Atoms of the same element with the same number of protons but different numbers of neutrons.

Alpha Radiation

Radiation consisting of alpha particles, which are emitted from the nucleus and are highly ionizing.

Beta Radiation

Radiation consisting of high-speed electrons emitted by a nucleus during radioactive decay.

Gamma Radiation

Electromagnetic radiation emitted during radioactive decay, with high penetration power and low ionization.

Half-life

The time required for half of the unstable nuclei in a sample to decay.

Activity

The rate at which a radioactive substance emits particles or radiation, measured in Becquerels.

Radioactive Decay

The process by which an unstable atomic nucleus loses energy by emitting radiation.

Nuclear Fission

The process of splitting a heavy nucleus into smaller nuclei, releasing a large amount of energy.

Nuclear Fusion

The process of combining small nuclei to form a heavier nucleus, releasing more energy than fission.