unit 3: the electron and the periodic table vocab

Anion

An ion that has a negative charge.

Atomic radius

One-half the distance between the center of identical atoms that are bonded together.

Cation

An ion that has a positive charge.

Electron affinity

The energy needed to remove an electron from a negative ion to form a neutral atom or molecule.

Electron configuration

The arrangement of electrons in an atom, which is prescribed by three rules-the aufbau principle, the Pauli exclusion principle, and Hund’s rule.

Electronegativity

Indicates the relative ability of an element’s atoms to attract electrons in a chemical bond.

Excited state

A state in which an atom has more energy than it does at its ground state.

Ground state

The lowest energy state of a quantized system.

Ion

An atom or bonded group of atoms with a positive or negative charge.

Ionization energy

The energy required to remove an electron from an atom or ion.

Noble-gas configuration

An outer main energy level fully occupied, in most cases, by eight electrons.

Orbital

A region in an atom where there is a high probability of finding electrons.

Periodic law

States that when the elements are arranged by increasing atomic numbers, their is a periodic repetition of their properties.

Periodic table

A chart that organizes all known elements into a grid of horizontal rows (periods) and vertical columns (groups of families) arranged by increasing atomic numbers.

Photon

A particle of electromagnetic radiation with no mass that carries a quantum of energy.

Quantum

The minimum amount of energy that can be gained or lost by an atom.

Quantum number

The number assigned to each orbit of an electron.

Quantum theory

The study of the structure and behavior of the atom and of subatomic particles from the view that all energy comes in tiny indivisible bundles.

Valence electrons

The electrons in an atom’s outermost orbitals; determine the chemical properties of an element.