(2743) The Periodic Table: Atomic Radius, Ionization Energy, and Electronegativity

Periodic Table

A table that organizes all known chemical elements based on their properties, atomic number, and electron configuration.

Dmitri Mendeleev

The chemist who created the first widely recognized periodic table that arranged elements into periods and groups, predicting the existence of unknown elements.

Valence Electrons

Electrons in the outermost shell of an atom that determine its chemical behavior.

Atomic Radius

The size of an atom, which increases down a group and decreases across a period.

Ionic Radius

The size of an ion, which can increase when an electron is added and decrease when an electron is removed.

Ionization Energy

The energy required to remove an electron from an atom, which generally increases across a period and decreases down a group.

Electron Affinity

The amount of energy released when an atom gains an electron, increasing for nonmetals as you go across a period.

Electronegativity

The ability of an atom to attract and hold onto electrons, generally increasing across a period.

Orbital Symmetry

The arrangement of electrons within an atom that can affect its stability and ionization energy.

Noble Gases

Elements in group 18 of the periodic table that have a full outer shell of electrons, making them particularly stable and unreactive.