CHEM 201 – Fall 2025 Lecture Notes

These flashcards cover key vocabulary and concepts from the CHEM 201 lecture notes focusing on light, atomic structure, and electromagnetic radiation.

Photons

Mass-less packets of energy that exhibit both wave-like and particle-like properties.

Atomic Emission Spectrum

A series of individual lines produced when light from excited gaseous atoms is refracted by a prism.

Electromagnetic Radiation

All forms of radiation, which can be described as sine waves comprising electric and magnetic fields.

Frequency (ν)

The number of cycles of a wave that occur in one second, measured in Hertz (Hz).

Wavelength (λ)

The distance between two successive peaks of a wave.

Planck’s Constant (h)

A physical constant used to describe the sizes of quanta in quantum mechanics, valued at 6.626 × 10^-34 Joule·sec.

Quantum Theory

A fundamental theory in physics that describes nature at the smallest scales, introducing the concept of quantization of energy.

Excited State

The energy state of an atom in which its electrons have absorbed energy and moved to a higher energy level.

Ground State

The lowest energy state of an atom, where electrons are in their closest possible configuration to the nucleus.

Emission Lines

Distinct lines that appear in the emission spectrum of elements, unique to each element.

Aurora

Natural light display in the Earth's sky, predominantly seen in high-latitude regions, caused by the interaction of solar wind with the Earth's magnetosphere.

X-ray Emission

The release of X-ray radiation, often used in detection methods for elements like mercury in biological samples.