6.2 The Bohr Model

Vocabulary flashcards covering key Bohr model concepts from the lecture notes.

Bohr model

Quantum model of the hydrogen atom with electrons in quantized circular orbits; photons are emitted or absorbed during transitions between orbits.

Hydrogen atom

Simplest atom with one proton nucleus and one electron; the system Bohr used to develop his model.

Stationary state hypothesis

Electron does not radiate while in a stationary orbit; radiation occurs only when transitioning between different orbits.

Photon

Quantum of light energy emitted or absorbed during a transition between energy levels (energy = hν = hc/λ).

Planck's constant (h)

Fundamental constant relating energy and frequency (E = hν); appears in Bohr’s and photon energy relations.

Rydberg equation

Relation for hydrogen spectral lines: 1/λ = R(1/n1^2 − 1/n2^2); R is the Rydberg constant.

Rydberg constant (R)

Constant used in the Rydberg equation; Bohr calculated a value that matched experimental results.

Quantized energy levels

Energies of electrons in atoms occur in discrete values described by quantum numbers.

Principal quantum number (n)

Integer label for electron energy levels (n = 1, 2, 3, …).

Ground state

Lowest energy electronic state of an atom (n = 1 for hydrogen).

Excited state

Any higher energy state (n > 1) reached by absorbing energy.

Hydrogen-like atoms

One-electron ions such as He+, Li2+, Be3+; energy levels depend on the nuclear charge Z.

Bohr radius (a0)

Distance scale of the hydrogen ground-state orbit; a0 ≈ 5.292×10^−11 m.

Hydrogen-like energy formula

E_n = −k Z^2 / n^2, with k = 2.179×10^−18 J; describes energy of the nth orbit in a hydrogen-like atom.

Ionization energy

Energy required to remove the electron completely (E → 0); for hydrogen ground state, ΔE = k = 2.179×10^−18 J.

Ionization limit

Energy level E = 0 corresponding to n → ∞; electron is no longer bound to the nucleus.

Limitations of Bohr model

Could not account for electron–electron interactions in multi-electron atoms; quantum mechanics later provided a better model.