Atomic Structure and Rutherford's Experiment Practice Flashcards

This set of vocabulary flashcards covers the historical models of the atom, details and components of Rutherford's gold foil experiment, and concepts related to radioactivity and ionisation based on lecture notes.

Dalton's atomic model

A modern atomic model proposed around $1800$, based on experimentation, which characterized atoms as tiny solid spheres.

Plum-pudding model

The atomic model proposed by J J Thomson in $1897$ following his discovery of the electron.

Ernest Rutherford

The scientist who directed the alpha particle scattering experiments in $1905$ and $1910$, leading to the discovery of the nucleus.

Alpha particle

A positively charged particle fired at thin gold foil to investigate the nature of atoms; it is less massive than a gold nucleus.

Nucleus

A small, very dense, positively charged object at the center of an atom where most of the mass is concentrated.

Ionised

The state of a substance, such as air, when its atoms or molecules become charged.

Zinc sulfide (ZnS) screen

A fluorescent circular coating used to detect the path of alpha particles by showing where they hit after passing through the gold foil.

Vacuum chamber

The evacuated space where the gold foil experiment was conducted to prevent alpha particles from being stopped or deflected by air molecules.

Narrow lead tube

The component used to house the alpha source, ensuring particles are emitted in a specific, directed path.

Empty space conclusion

The inference made from the observation that most alpha particles went straight through gold atoms undeflected.

Large-angle deflection

The observation that a very small percentage of alpha particles bounced back, indicating the existence of a small, massive, and positively charged nucleus.

Technetium-99

A radioactive tracer used in medical diagnoses with a half-life of $6\,\text{hours}$ that emits only gamma rays.

Gamma rays

Emissions from Technetium-99 that have very little ionising ability.

Lead screens

Components used in the experiment to shield or narrow the path of alpha particles.

Geiger and Marsden

The scientists who performed the series of gold foil experiments under the direction of Ernest Rutherford.