Models of the Atom

This set of flashcards covers key vocabulary and concepts related to the various models of the atom discussed in the lecture.

Plum Pudding Model

An early model of the atom where positive matter has negative electrons dispersed throughout.

Rutherford Experiment

An experiment that disproved the Plum Pudding Model and led to the understanding of the atomic nucleus.

Alpha Particles

Positively charged particles used in Rutherford's gold foil experiment.

Gold Foil Experiment

An experiment by Rutherford that established the existence of a small, dense nucleus within the atom.

Deflection

The change in direction of alpha particles when they hit the nucleus of an atom.

Major Deflection

When alpha particles bounce back after striking a nucleus, indicating a dense positive center.

Empty Space in Atom

The conclusion drawn from the Rutherford Experiment that most of an atom is empty space.

Positive Component of Atom

The nucleus containing protons, which is responsible for the positive charge in an atom.

Niels Bohr

A physicist who developed the planetary model of the atom.

Planetary Model

Model proposed by Bohr that depicted electrons orbiting the nucleus like planets around the sun.

Orbitals

Paths around the nucleus where electrons are likely to be found at specific energy levels.

Excited State

State in which an electron has gained energy and moved to a higher orbital.

Ground State

The lowest energy state of an electron in an atom.

Spectral Lines

Unique lines produced by elements when electrons transition between energy levels.

Hydrogen Emission Spectrum

The spectrum of light emitted by hydrogen atoms when their electrons transition back to the ground state.

Wave Mechanical Model

The current model of the atom that incorporates principles of wave mechanics to describe electron behavior.

Uncertainty Principle

The principle stating that the exact position and momentum of an electron cannot be known simultaneously.

Clouds

Regions around the nucleus where there is a high probability of finding an electron.

Element Identification

The process of determining an element's identity based on its unique spectral lines.

Quantum Chemistry

The study of how quantum mechanics applies to atoms and molecules.

Rutherford's Findings

Most alpha particles passed through gold foil, some were deflected, few bounced back.

Lead Shield

Used in Rutherford's experiment to contain the radioactive source.

Detecting Screen

The material used to observe the impacts of alpha particles in Rutherford's experiment.

Electrical Charge

A property of subatomic particles that determines how they interact with each other.

Chemical Behavior

How atoms interact and combine based on electron arrangements.

Helium Nucleus

The nucleus composed of two protons and two neutrons, which alpha particles resemble.

Electrons

Negatively charged subatomic particles that occupy orbitals around the nucleus.

Directional Change

When an alpha particle's path alters due to interaction with an atom's nucleus.

Majority of Alpha Particles

The alpha particles that traveled straight through the gold foil without deflection.

Minor Deflections

Slight changes in the direction of alpha particles after contact with a nucleus.

Atom Composition

The arrangement and types of subatomic particles within an atom.

Rutherford's Model Issue

Rutherford’s model lacked explanation for electron stability and distribution.

Electron Energy Levels

Quantized states in which electrons can exist around the nucleus.

Quantum Mechanics

The branch of physics relating to the very small scales of particles like electrons.

Energy Release

The process by which an excited electron returns to ground state and emits light.

Chocolate Chip Cookie Analogy

The description of the Plum Pudding Model depicting electrons as chips in a positive dough.

Positive Plate

The plate that attracts the negative beam in the context of the Plum Pudding Model.

Subatomic Particles

Particles smaller than atoms, such as protons, neutrons, and electrons.

Atomic Structure

The arrangement and interaction of subatomic particles in an atom.

Radioactive Source

Material emitting radiation used in Rutherford's experiment.

Helium Atom

An atomic structure composed of two protons, two neutrons, and typically two electrons.

Energy Absorption

When an electron acquires energy and moves to a higher orbital.

Energy Emission

The release of energy in the form of light when an electron transitions to a lower state.

Unique Spectral Lines

Distinct patterns of light emitted or absorbed by different elements.

Atom Discovery

Process through which scientists developed models to explain atomic behavior.

Subatomic Composition

The specifics of protons, neutrons, and electrons that make up an atom.

Detection of Alpha Particles

The act of observing the behavior of alpha particles using detecting screens.

Nucleus Size

The small and dense center of an atom that contains positively charged protons.

Electron Motion

The behavior of electrons as they move in orbitals around the nucleus.

Scientific Model

An illustrative representation of scientific concepts based on empirical evidence.

Elemental Behavior

The characteristics and reactions of elements due to their atomic structure.

Rutherford's Contribution

Rutherford's findings led to the discovery of the atomic nucleus and changed atomic models.

Energy Quanta

Discrete packets of energy associated with electron movement between orbitals.

Atomic Mass Unit

A standard unit that quantifies mass in atomic and molecular scales.

Orbital Shape

The three-dimensional region where there is a high probability of finding an electron.

Cloud Density

Indicates areas around the nucleus where electrons are most likely to be found.

Science Evolution

The progressive improvement and refinement of theories and models in science.

Standard Model

A model describing fundamental particles and their interactions in physics.

Plum Pudding vs. Rutherford Model

The contrast between the early and later theories of atomic structure.

Invention of Spectroscopes

An advancement that allowed scientists to observe spectral lines of elements.