Modern Atomic Theory Practice Flashcards

Vocabulary-style flashcards covering the Atomic Theory lecture notes, including nomenclature, properties of light, atomic models, and periodic table trends.

Nucleus

The small dense center of an atom that is positively charged, contains protons and neutrons, and is surrounded by mostly empty space.

Proton

A subatomic particle found in the nucleus with a $+1$ charge.

Neutron

A subatomic particle found in the nucleus with no charge.

Electron

A subatomic particle with a $-1$ charge that moves in the space around the nucleus.

Wavelength ($\lambda$)

The distance between two peaks or troughs in a wave.

Frequency ($v$)

The number of waves (cycles) per second that pass a given point in space.

Speed of light ($c$)

The speed at which electromagnetic radiation travels, defined as $2.9979 \times 10^{8}\,\text{m/s}$.

Photon

A packet of energy that represents a particle of light.

Excited state

A state in which an atom has excess energy after receiving energy from an outside source.

Ground state

The lowest possible energy state of an atom.

Quantized Energy Levels

Discrete energy levels where only certain energy changes can occur, meaning the atom can only produce specific types of photons.

Bohr Model

A model of the atom that proposed electrons move in circular orbits and jump between quantized energy levels by absorbing or emitting photons; this model was later found to be incorrect.

Wave Mechanical Model

A model of the atom that uses orbitals to describe the probability of finding an electron in a certain space, rather than its exact path or movement.

Orbital

A potential space for an electron, arbitrarily defined as the sphere that contains 90\% of the total electron probability.

Principal energy levels

The discrete energy levels of an atom labeled with whole numbers ($n = 1, 2, 3, \text{etc.}$).

Sublevels

Divisions within principal energy levels labeled with numbers and letters ($s, p, d, f$) that indicate the shape of the orbital.

s orbital

A spherical-shaped orbital.

p orbital

A two-lobed orbital; the subscripts $x, y,$ or $z$ indicate which coordinate axis the lobes lie along.

Spin

A property of electrons where they rotate like a top.

Pauli Exclusion Principle

The rule stating that an atomic orbital can hold a maximum of 2 electrons, and those electrons must have opposite spins.

Electron configuration

A notation representing the arrangement of electrons in an atom (e.g., $1s^{1}$).

Orbital diagram

A visual representation of electron arrangement where orbitals are boxes grouped by sublevel containing arrows to represent electrons.

Valence electrons

Electrons located in the outermost (highest) principal energy level of an atom.

Core electrons

The inner electrons of an atom that are not in the outermost principal energy level.

Lanthanide series

A group of fourteen elements occurring after Lanthanum that corresponds to the filling of the seven $4f$ orbitals.

Actinide series

A group of fourteen elements occurring after Actinium that corresponds to the filling of the seven $5f$ orbitals.

Ionization Energy

The energy required to remove an electron from a gaseous atom or ion, represented by the equation $X(g) \rightarrow X^{+}(g) + e^{-}$.

Atomic size

The radius of an atom, which generally decreases across a period from left to right and increases moving down a group.