Chem 7

wavelength

Distance from the crest of one wave to the crest of the next wave.

frequency

Number of waves which pass a given point in one second.

Hertz

Unit for frequency.

excited

Term for an electron which has absorbed energy and is occupying a higher energy level than would be normal.

ionization energy

Energy required to remove one electron from an atom.

valence electrons

Electrons used for bonding; found in the highest s and p energy levels.

atomic radius

Distance from the nucleus to the outermost electron.

electronegativity

Ability of an atom to attract electrons when it is in a covalent bond.

ground state

State of lowest energy for an atom.

electron affinity

Energy change when an electron is added to an atom in ground state.

Aufbau principle

Principle which says an electron enters the lowest energy state orbital available to it.

principle energy number

Quantum number which tells the average energy and distance from the nucleus; first quantum number.

magnetic number

Quantum number which designates the specific orbital in one level of orbitals; 3rd quantum number.

spin number

Quantum number which designates the orientation of the electron in an orbital; must be +1/2 or -1/2.

Planck

Found the constant relating energy to frequency.

Bohr

Made the first model of the atom showing electrons traveling in circular paths at specific distance.

Schrödinger

Proposed the calculus equations that allowed us to calculate quantum levels.

Pauli

Said that no two electrons can have the same 4 quantum numbers.

Hund

Proposed the idea that all orbitals of the same energy level must contain one electron before any orbital can contain two electrons.

Rydberg

Calculated the average amount of energy in a principal energy level; created the constant to do this.

de Broglie

Proposed that electrons behaved like members of the electromagnetic spectrum and were both waves and particles.

Einstein

Explained the photoelectric effect; explained why some frequencies of light could cause current to flow in a metal.