Development of the Atomic Model and Wave-Particle Nature of Light

Vocabulary flashcards covering the historical development of atomic models, electromagnetic radiation, quantum theory, atomic spectra, and rules for electron configurations.

Electromagnetic Radiation

A form of energy that travels thru space like a wave at a constant speed of $3.0 \times 10^8\,\text{m/s}$, with examples including visible light, microwaves, X-rays, and radio waves.

Wavelength ($\lambda$)

The distance between corresponding points of adjacent waves, typically ranging from meters ($\text{m}$) to nanometers ($\text{nm}$).

Frequency ($\nu$)

The number of waves that passes a given point in a specific amount of time, measured in units of $1/\text{second}$ or $\text{Hz}$ (hertz).

Wave Equation for Light ($c = \lambda \nu$)

The mathematical relationship where speed of light ($c = 3.0 \times 10^8\,\text{m/sec}$) equals wavelength ($\lambda$) multiplied by frequency ($\nu$), showing that wavelength and frequency are inversely proportional.

Photoelectric Effect

The emission of electrons from a metal when light shines on the metal, creating an electric current only if the light's frequency meets or exceeds a specific minimum threshold.

Quanta

Small, specific amounts of energy emitted by hot objects, defined as the minimum amount of energy that can be gained or lost by an atom.

Planck's Constant ($h$)

A fundamental constant equal to $6.626 \times 10^{-34}\,\text{J}\cdot\text{s}$, used in the equation $E = h\nu$ to relate the energy of a quantum ($E$) directly to radiation frequency ($\nu$).

Photon

A particle of electromagnetic radiation having no mass and carrying a quantum of energy, as introduced by Albert Einstein.

Ground State

The lowest energy state of an atom.

Excited State

A state in which an atom has a higher potential energy than it has in its ground state.

Line-Emission Spectrum

A series of specific frequencies of visible light produced when the electromagnetic radiation emitted by excited atoms returning to their ground state is passed through a prism.

Bohr Model

An atomic model in which electrons circle the nucleus only in specific allowed paths called orbits, each with a fixed, definite energy.

Electron Configuration

The arrangement of electrons in an atom.

Aufbau Principle

The rule stating that an electron occupies the lowest-energy orbital that can receive it, beginning with the $1s$ orbital.

Pauli Exclusion Principle

The rule stating that no two electrons in the same atom can have the same set of 4 quantum numbers, requiring two electrons occupying the same orbital to have opposite spins.

Hund's Rule

The rule stating that orbitals of equal energy are each occupied by one electron before any orbital is occupied by a second electron, and all electrons in singly occupied orbitals must have the same spin.

Noble Gas Notation

A shortcut for electron configuration that uses the symbol of the closest previous noble gas enclosed in brackets to represent an outer main energy level fully occupied by 8 electrons.