Chapter_3_ELECTRON_CONFIGURATIONS

Modern Atomic Theory

The most accurate depiction of what an atom looks like and how it behaves based on various atomic models.

Nucleus

The central part of an atom comprising protons and neutrons.

Proton

A positively charged subatomic particle located in the nucleus.

Neutron

A neutral subatomic particle located in the nucleus.

Electron

A negatively charged subatomic particle that exists outside the nucleus, occupying energy levels.

Energy Levels

Regions around the nucleus where electrons can exist with specific quantized energies.

Quantized Energy Levels

Specific energy levels occupied by electrons, where energy values are not continuous.

Bohr Model

An early atomic model proposed by Niels Bohr, suggesting that electrons orbit the nucleus at defined energy levels.

Ground State Energy

The lowest energy state of an electron in an atom.

Excited States

Higher energy levels that can be occupied by electrons when they absorb energy.

Photon

A discrete particle of light emitted when an electron returns from an excited state to the ground state.

Quantum Mechanical Model

A modern atomic model that describes electrons in probability regions called orbitals.

Orbitals

Regions around the nucleus where there is a high probability of finding an electron.

Sublevels

Sections within energy levels, designated by letters s, p, d, f, which contain orbitals.

Hund's Rule

The principle stating that electrons will occupy orbitals singly before pairing up.

Valence Electrons

Electrons located in the outermost energy level of an atom.

S Block

The section of the periodic table that includes hydrogen and alkali metals.

P Block

The section of the periodic table that includes nonmetals and metalloids.

D Block

The section of the periodic table that includes transition metals.

F Block

The section of the periodic table that includes lanthanides and actinides.

Electron Configuration

The arrangement of electrons in an atom's orbitals, often represented using notation.

Abbreviated Notation

A shorthand way to write electron configurations using noble gas core.

Atomic Radius

A measure of the size of an atom, typically increasing down a group and decreasing across a period.

Ionization Energy

The energy required to remove an electron from an atom in its gaseous state.