Chapter 11: Modern Atomic Theory

Electromagnetic Radiation
Radiant energy that exhibits wave-like behavior & travels through space at the speed of light in a vacuum.
The distance between two consecutive peaks or troughs in a wave.
A “particle” of electromagnetic radiation.
Quantized Energy Levels
Certain discreet energy levels of an atom.
Wave Mechanical Model
Electron states are described by orbitals.
A representation of the space occupied by an electron in an atom; the probability distribution for an electron.
Principal Energy Levels
Discrete & limited energy levels of an atom.
Divisions of principle energy levels containing the s, p, d, & f blocks.
Pauli Exclusion Principle
An atomic orbital can hold a maximum of two electrons, & those two electrons must have opposite spins.
Electron Configuration
Orbital level with the represented electrons.
Orbital (Box) Diagram
Orbitals & their categories represented by boxes & arrows signaling opposite spin.
Valence Electrons
The electrons in the outermost occupied principal quantum level of an atom.
Core Electrons
Inner electrons in an atom; one that is not in the outermost (valence) principal quantum level.
Lanthanide Series
A group of 14 elements following lanthanum on the periodic table, in which the 4f orbitals are being filled.
Actinide Series
A group of 14 elements following actinium on the periodic table in which the 5f orbitals are filled.
Main-Group Representative Elements
Elements in group 1-8 on the periodic table. The group number gives the sum of the valence s & p electrons.
Elements that give up electrons relatively easily & are typically lustrous, malleable, & a good conductor of electricity.
An element that does not exhibit metallic characteristics. Chemically, a typical nonmetal accepts electrons from a metal.
An element that has both metallic & nonmetallic properties.
Atomic Size
As the principal energy level increases or decreases, so does the atomic size.
Ionization Energy
The quantity of energy required to move an electron form a gaseous atom or ion.