Chapter 2: Electrons and the Periodic Table

Vocabulary flashcards generated from Chapter 2: Electrons and the Periodic Table covering light, Bohr's atom, quantum mechanical orbitals, electron configurations, periodic trends, and ions.

Wavelength ($\lambda$)

The distance between identical points on successive waves.

Frequency ($\nu$)

The number of waves that pass through a particular point in one second.

Line Spectra

Emission spectra that are not continuous, but contain only discrete lines corresponding to specific wavelengths of light.

Photons

Tiny, discrete packets of light energy.

Ground State

The lowest possible energy level of an electron in an atom, designated as $n = 1$ in the Bohr model.

Excited States

Energy levels higher than the ground state, where the quantum number $n$ is an integer greater than 1 ($n = 2, 3, 4, 5 \times \frac{1}{1}\text{...}$).

Atomic Orbital

A region of space defined by quantum mechanics where an electron is most likely (approximately 90% probability) to be found.

Principal Energy Levels (Shells)

Main energy levels of an atom designated by integer quantum numbers $n$ ($n = 1, 2, 3, \text{...}$) containing one or more sublevels.

Energy Sublevels (Subshells)

Subdivisions of principal energy levels designated as $s$, $p$, $d$, or $f$, each containing a fixed number of orbitals.

s Orbitals

Spherical atomic orbitals present in every principal energy level ($n \text{ starting at } 1$) with electron density concentrated near the nucleus.

p Orbitals

Dumbbell-shaped atomic orbitals that lie along perpendicular axes ($p_x$, $p_y$, $p_z$), beginning at the second principal energy level ($n = 2$).

d Orbitals

A group of five atomic orbitals available starting in the third principal energy level ($n = 3$).

Electron Configuration

A list of numbers and letters indicating the specific arrangement of electrons in an atom's energy sublevels.

Orbital Diagram

A pictorial representation of electron configuration where square boxes represent orbitals and arrows represent electron spins.

Pauli Exclusion Principle

The rule stating that an orbital can accommodate a maximum of two electrons, and those two electrons must have opposite spins.

Hund's Rule

The rule stating that orbitals of equal energy in the same sublevel will each receive one electron with parallel spins before any orbital receives a second electron.

Valence Electrons

The outermost electrons in an atom that reside in the shell with the highest principal quantum number ($n$).

Core Electrons

The inner electrons of an atom that occupy filled lower principal energy levels beneath the valence shell.

Lewis Dot Symbols

Representations of main-group elements or ions in which valence electrons are displayed as dots arranged around the chemical symbol.

Ionization Energy

The energy required to remove an electron from an atom in the gas phase.

Electron Affinity

The measure of an atom's ability or ease in gaining an electron.

Cation

A positively charged atomic ion formed when a neutral atom loses one or more electrons.

Anion

A negatively charged atomic ion formed when a neutral atom gains one or more electrons.

Isoelectronic

Having the exact same electron configuration as another atom or ion, such as main-group ions taking on noble gas configurations.