EM Spectrum, Oxidation States, and Photoelectric Effect (Vocabulary)

Vocabulary flashcards covering oxidation states, Planck's constant, photon energy, EM spectrum, visible light, and the photoelectric effect, based on the provided lecture notes.

Oxidation state

A bookkeeping value assigned to an atom in a compound to reflect its apparent electron ownership during bonding; in free elements the oxidation state is zero; in ions the sum of oxidation states equals the ion’s charge.

Zero oxidation state (free element)

An atom in a free element has oxidation state zero.

Sum of oxidation states equals ion charge

For a charged species, the sum of all oxidation states equals the overall ionic charge.

Neutral compound rule

In a neutral compound, the sum of oxidation states of all atoms is zero.

Planck's constant (h)

A fundamental constant that relates photon energy to frequency via E = hν.

Frequency (ν)

The number of wave cycles per second; unit s⁻¹ (Hertz).

Wavelength (λ)

The distance between successive wave crests; inversely related to frequency by c = λν.

Speed of light (c)

The constant speed at which light propagates in vacuum; c ≈ 3.00 × 10^8 m/s; links wavelength and frequency through c = λν.

Photon energy

The energy carried by a single photon, given by E = hν.

Electromagnetic radiation

Energy that propagates as EM waves and can be described by wave-like and particle-like (photon) pictures.

Electromagnetic spectrum

The entire range of EM radiation from long-wavelength radio waves to high-energy gamma rays; visible light is only a small portion.

Visible light

The portion of the EM spectrum detectable by the human eye; occupies a narrow range of wavelengths.

Wave-particle duality

A property of EM radiation that shows both wave-like and particle-like behavior depending on the experiment.

Photoelectric effect

Emission of electrons from a material surface when light shines with sufficient photon energy; demonstrates quantized energy.

Threshold energy

Minimum photon energy required to overcome a material’s work function and eject an electron.

Photocurrent

Electric current produced by photoemitted electrons collected at a detector.