### Atomic Emission Spectrum

the pattern formed when light passes through a prism or diffraction grating to separate it into the different frequencies of light it contains

### Atomic Orbital

a mathematical expression describing the probability of finding an electron at various locations; usually represented by the region of space around the nucleus where there is a high probability of finding an electron

### Electromagnetic Radiation

energy waves that travel in vacuum at a speed of 2.998 x10^8 m/s; includes radio waves, microwaves, infrared waves,visible light, ultraviolet waves, x-rays, and gamma rays

### Electron Configurations

the arrangement of electrons of an atom in its ground state into various orbitals around the nuclei of atoms

### Heisenberg Uncertainty Principle

says it is impossible to know exactly both the velocity and the position of a particle at the same time

### Hund's Rule

electrons occupy orbitals of the same energy in a way that makes the number of electrons with the same spin direction as large as possible

### Parli Exclusion Principle

an atomic orbital may describe at most two electrons, each with opposite spin direction

### Photon

a quantum of light, a discrete bundle of electromagnetic energy that interacts with matter similarly to particles

### Quantum Mechanical Model

the modern description, primarily mathematical, of the behavior of electrons in atoms

### Spectrum

wavelengths of visible light that are separated when a beam of light passes through a prism, range of wavelengths of electromagnetic radiation