Quantum Numbers A set of numbers, whose values describe the probable location of an electron around a nucleus

Bohr & Hydrogen Bohr’s model was able to explain hydrogen’s electron distribution Where light and atoms combine: Energy Overlap: Summary of Niels Bohr: Bohr calculated the wavelengths of light that would be emitted by excited Hydrogen atoms. Bohr connected the unseen world (atoms) to the seen (observable, predictable spectral lines). But his model could not explain atom’s with more than one electron

Laws of Physics In physics, you study “Classical Mechanics”, the study of the motion of macroscopic objects; ie planets around a star, a ball being thrown or a ladder slipping away from a wall etc.

Laws of Physics Where physics and chemistry overlap, is “Quantum Mechanics”; the study of atomic particles. The “classical” rules of motion do not apply because atomic particles behave like waves.

Principal Quantum # (n) Describes an orbital’s size or distance from nucleus Bohr’s model included this Energy Level or “shell” of electron Range: n = 1 to infinity

Secondary Quantum # (l) The shape of electron orbital Called “subshells” Describes motion of electron within a shell 4 domains of motion s, p, d, f Range: from 0 to n-1

Magnetic Quantum # (ml) Each subshell has limited “slots” for electron pairs The slots are called orbitals Range: -l to l

Spin Quantum # (ms) Each orbital holds two electrons Electrons are both negatively charged, but do not repel within an orbital The have opposite spins to prevent repulsion

Summary l l = 0 to n-1 Name Symbol Range Brief Description Principal n Energy Level (Shell) Secondary l l = 0 to n-1 Subshell (s=1, p=2, d=3 & f=4) Magnetic ml ml = -l to l Orbital (orientation in 3D space) Spin m s m s= -½ to +½ Spin (either up or down within same subshell)