Unit 4: Electron Models, Quantum Numbers, and Electron Configuration in Chemistry

Electron

A negatively charged subatomic particle.

Balanced Atom

An atom with the same number of protons and electrons.

Bohr Model

A model of the atom with protons and neutrons in the nucleus and electrons orbiting in circular energy levels.

Energy Level

A region of an atom in which electrons of the same energy are (likely) to be found.

Valence Electrons

Electrons in the outermost energy level.

Heisenberg Uncertainty Principle

A fundamental law of quantum mechanics that states it is impossible to simultaneously know the exact position and momentum of a particle.

Quantum State

The state of an electron described by quantum numbers.

Principal Quantum Number

A number that indicates the energy level of an electron in an atom.

Angular Momentum Quantum Number

A number that determines the shape of an electron's orbital.

Magnetic Quantum Number

A number that specifies the orientation of an orbital.

Spin Quantum Number

A number that indicates the spin direction of an electron.

Pauli Exclusion Principle

A principle stating that no two electrons in an atom can have the same set of quantum numbers.

Hund's Rule

A rule stating that electrons will occupy degenerate orbitals singly before pairing up.

Aufbau Principle

A principle stating that electrons occupy the lowest energy orbitals first.

s, p, d, and f blocks

Categories of elements in the periodic table based on their electron configurations.

Orbital Filling Diagram

A diagram that shows the distribution of electrons in an atom's orbitals.

Electron Configuration

The arrangement of electrons in an atom's orbitals.

Noble Gas Abbreviated Electron Configuration

A shorthand notation for electron configuration using the nearest noble gas.

Wave-Particle Duality

The concept that every particle or quantum entity may be described as either a particle or a wave.

Observation Limitations

The restrictions on measuring properties of electrons due to their small size and the effects of measurement.

Energy Level Spacing

The difference in energy between different energy levels in an atom.

Distance from the Nucleus

The space between the nucleus of an atom and its electrons.

Electron Interaction with Light

When light interacts with an electron, the electron's momentum is significantly altered.

Quantum Model

A model of the atom that incorporates quantum mechanics to describe electron behavior.

Classical Bohr Model

An early model of the atom that depicts electrons in fixed orbits around the nucleus.