Atoms Mind Map

Alpha-particle scattering is the experiment in which fast alpha particles are directed at a thin gold foil and their deflections are observed. Rutherford's model states that most of the atom is empty space, with nearly all positive charge and mass concentrated in a very small central nucleus.

In answers, connect each observation to one inference: straight passage means empty space, large deflection means concentrated positive charge, and rare rebound means a very small but massive nucleus.

The limitations of Rutherford's model are the failures that arise when classical electromagnetic theory is applied to orbiting electrons: it cannot explain atomic stability or the discrete line spectra of atoms.

Use the phrase accelerating charge radiates energy, then connect it to collapse of orbit and absence of fixed energy levels.

Bohr's model of hydrogen states that the electron can revolve only in certain stable stationary orbits without radiating energy, and radiation is emitted or absorbed only when the electron jumps between allowed energy levels.

Always identify initial and final levels first. For emission, higher n to lower n; for absorption, lower n to higher n.

The hydrogen atom has discrete energy levels given by En = -13.6/n^2 eV, and spectral lines are produced when electrons make transitions between these levels. Different final levels form different spectral series.

For spectral series, classify by the final level: Lyman ends at 1, Balmer ends at 2, Paschen ends at 3.

de Broglie's explanation says that an electron in a stable Bohr orbit behaves as a matter wave forming a standing wave around the nucleus, so the circumference of the orbit must contain an integral number of wavelengths: 2πr = nλ.

In derivations, start from the standing-wave condition and then substitute λ = h/mv to reach mvr = nh/2π.