Structure of the Atom and Changing Atomic Models

Vocabulary flashcards covering atomic structure, subatomic particle properties, classification of matter, and key historical transitions among atomic models.

Matter Classification

The categorization of matter as an element, compound, homogeneous mixture, or heterogeneous mixture, based on its composition and particle arrangement.

Subatomic Particles

The three fundamental particles found inside an atom, consisting of protons, neutrons, and electrons.

Electron

A subatomic particle that carries a negative charge and occupies fixed energy levels surrounding the nucleus.

Nucleus

The dense, positive central area of an atom where protons and neutrons are located and where most of an atom's mass is concentrated.

Neutral Atom

An atom containing equal numbers of positive protons and negative electrons, such that an atom with $8$ protons must have $8$ electrons.

Model Replacement Principle

The rule stating that each atomic model was replaced only when new experimental evidence could no longer be explained by the old model.

Dalton to Thomson Transition

The progression in atomic model history where discovering the electron demonstrated that atoms are not solid, indivisible spheres after all.

Gold Foil Experiment

The experiment that facilitated the transition from Thomson to Rutherford by revealing a dense, positive nucleus surrounded by mostly empty space.

Rutherford to Bohr Transition

The transition in atomic theory that established fixed energy levels to explain why electrons do not simply spiral into the nucleus.

Atomic Identifiers

The two metrics used to describe atomic structure and locate protons, neutrons, and electrons: the atomic number and mass number.