The Quantum-Mechanical Model of the Atom (Lecture Notes)

Vocabulary flashcards covering key terms from the Quantum-Mechanical Model of the Atom lecture notes.

Electromagnetic radiation

Energy that travels through space as waves and particles; includes visible light and other wavelengths.

Wavelength (λ)

Distance between corresponding points on adjacent waves; determines color and energy of photons.

Frequency (ν)

Number of waves passing a point per unit time; measured in hertz (Hz).

Amplitude

Height of a wave crest; relates to light brightness.

Speed of light (c)

Constant velocity of light in vacuum: 3.00 × 10^8 m/s.

Planck's constant (h)

6.626 × 10^-34 J·s; relates photon energy to frequency.

Photon

A quantum of light with energy E = hν.

Energy of a photon (E = hν)

Photon energy equals Planck's constant times frequency.

Photon energy in terms of wavelength (E = hc/λ)

Photon energy expressed using wavelength instead of frequency.

Quanta

Discrete packets of energy in radiation.

Photoelectric effect

Emission of electrons from a metal surface when illuminated with sufficient energy.

Work function (φ)

Minimum energy required to eject an electron from a metal surface.

Line spectrum

A spectrum consisting of discrete wavelengths emitted or absorbed by atoms.

Bohr model

Electrons occupy discrete allowed energy levels; transitions between levels emit/absorb photons.

Energy level

Discrete energy values associated with electron orbits.

Energy transition

Electron movement between energy levels with absorption or emission of a photon.

Emission spectrum

Bright lines at specific wavelengths emitted by excited atoms.

Absorption spectrum

Dark lines where photons are absorbed, revealing missing wavelengths.

Hydrogen emission lines (Balmer/Lyman series)

Series of spectral lines from electron transitions in hydrogen.

de Broglie wavelength

Matter waves: λ = h/p; momentum p = mv.

Momentum (p)

Mass × velocity; p = mv.

Uncertainty principle

Cannot simultaneously know exact position and momentum; ΔxΔp ≥ ħ/2.

Schrödinger equation

Wave equation describing the quantum state evolution using a wave function.

Wave function (ψ)

Mathematical description of a quantum state; its square gives probability density.

Probability density (ψ^2)

Probability of finding an electron in a given region of space.

Orbital

Region in space with high probability of finding an electron; described by quantum numbers.

Quantum numbers

n, l, ml, ms; specify energy, shape, orientation, and spin of orbitals.

Principal quantum number (n)

Describes energy level; n = 1, 2, 3, …

Angular momentum quantum number (l)

Defines orbital shape; 0 ≤ l ≤ n−1; s(0), p(1), d(2), f(3).

Magnetic quantum number (m_l)

Orientation of orbital; −l ≤ m_l ≤ l; number of orbitals per subshell.

Spin quantum number (m_s)

Electron spin; values +1/2 or −1/2.

s orbital

Spherically symmetrical orbital with l = 0.

p orbital

Dumbbell-shaped orbital with l = 1; oriented along axes.

d orbital

Five orbitals with more complex shapes (cloverleaf or donut-like); l = 2.

f orbital

Seven complex orbitals (l = 3) with intricate shapes.

Nodes

Regions where the probability density is zero; present in s, p, d, f orbitals.

Shell vs subshell

Shell: set of orbitals with same n; subshell: orbitals with same l within a shell.

MRI and electron spin

Magnetic Resonance Imaging uses electron spin states in a magnetic field to visualize tissues.

Interference

Constructive interference increases amplitude; destructive interference reduces it.

Diffraction

Bending of waves around obstacles, enabling color separation and X-ray analysis.

Visible spectrum range

Approximately 4.0 x 10^-7 m to 7.5 x 10^-7 m.