Basic Atomic Structure and Nuclear Chemistry

These flashcards cover key vocabulary and concepts from the study of atomic structure and nuclear chemistry.

Atom

The basic unit of a chemical element, consisting of protons, neutrons, and electrons.

Atomic Mass

The mass of an atom, typically expressed in atomic mass units (amu), which accounts for the total number of protons and neutrons.

Isotope

Atoms of the same element that have the same number of protons but different numbers of neutrons, resulting in different mass numbers.

Quantum Model

A model of the atom proposing that electrons exist in a cloud of probability rather than in fixed orbits.

Electron Configuration

A description of the occupation of the electron orbitals of an atom, typically expressed in the format that shows distribution among the different orbitals.

Ionization Energy

The energy required to remove an electron from an atom or ion, generally increasing across a period and decreasing down a group in the periodic table.

Electronegativity

The measure of the tendency of an atom to attract a bonding pair of electrons; it generally increases across a period and decreases down a group.

Radioactivity

The process by which unstable atomic nuclei lose energy by emitting radiation, including alpha, beta, and gamma radiation.

Alpha Radiation

A type of radiation consisting of helium nuclei; it has a positive charge and is relatively heavy.

Beta Radiation

A type of radiation consisting of electrons that are emitted from an atom when a neutron decays into a proton.

Gamma Radiation

High-energy electromagnetic radiation emitted during radioactive decay, which has no mass or charge.

Half-Life

The time required for half of the radioactive nuclei in a sample to decay into products.

Periodic Trends

The observable patterns in the properties of elements across the periodic table, including atomic size, ionization energy, and electronegativity.

Aufbau Principle

The principle stating that electrons occupy the lowest energy orbitals available first.

Pauli Exclusion Principle

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

Hund's Rule

A rule that states electrons fill degenerate orbitals singly before filling them in pairs, maximizing the number of unpaired electrons.