Atomic Structure & Periodicity — 7 Terms Defined

Inner Transition Element Atomic Structure & Periodicity Dimensionless An element of the lanthanide or actinide series, in which f orbitals are being filled. (n−2)f orbitals filling

Ionic Radius Atomic Structure & Periodicity pm The effective radius of an ion within a crystal lattice, deduced from measured interionic distances.

Ionisation Energy Atomic Structure & Periodicity kJ/mol The minimum energy needed to remove the most loosely held electron from one mole of gaseous atoms in their ground state. X(g) → X⁺(g) + e⁻

Isobar Atomic Structure & Periodicity Dimensionless One of a set of atoms of different elements that share the same mass number but have different atomic numbers. same A, different Z

Isoelectronic Species Atomic Structure & Periodicity Dimensionless Atoms or ions that possess the same number of electrons and the same electron configuration.

Isotone Atomic Structure & Periodicity Dimensionless One of a set of nuclides that contain the same number of neutrons but different numbers of protons. same N, different Z

Isotope Atomic Structure & Periodicity Dimensionless One of two or more atoms of the same element that differ in neutron number and therefore in mass. same Z, different A