Electron Structure

Huygens

________ explained "reflection "and "refraction "of light in terms of light waves traveling through the "ether.

Planck

________ (1900) assumed energy can only be absorbed or released in discrete amounts called Quanta.

Photoelectric effect

________: electrons are ejected from metals when hit with light of sufficient energy.

Energy

________ is emitted or absorbed as a photon where E= hv.

metal

Each ________ has a different energy at which it ejects electrons.

Electrons

________ exist only in certain discrete energy levels, which are described by quantum numbers.

Emission Spectra

emission of light from electronically-excited gas atoms

Blackbody Radiation

light is emitted from a hot object

Matter can absorb or emit energy only as whole

number multiples of hv, 2hv, 3hv, 4hv

Photoelectric effect

electrons are ejected from metals when hit with light of sufficient energy

Threshold energy

the energy at which a metal ejects its electrons

Spectrum

results when light from a source is separated into its different wavelength components

Balmer Series (1885)

Line spectrum of hydrogen in the visible region

Bohr's postulates

Only orbits of certain radii are allowed for the electron in a hydrogen atom.

An electron in an “allowed” orbit has an “allowed” energy and will not radiate energy.

Energy is emitted or absorbed by the electron as it changes from one allowed state to another. Energy is emitted or absorbed as a photon where E = hv

Limitations of the bohr model

Only works for the hydrogen atom

Radiation appears to have wavelike as well as particle-like character; model does not account for this

Model avoids the issue of why the negatively-charged particle does not spiral into the positively-charged nucleus