Vocab

Group: A column of elements in the periodic table that share similar properties.

Metal: An element that is shiny, can conduct heat and electricity, and is usually bendable.

Metalloid: An element with properties of both metals and nonmetals.

Nonmetal: An element that is usually dull and doesn't conduct heat or electricity well.

Period: A row of elements in the periodic table that have the same number of electron shells.

Periodic Law: The idea that elements' properties repeat in a predictable way as you go across the periodic table.

Periodic Table: A chart that arranges elements by their atomic number and shows their properties.

Actinide: A group of 15 elements that are radioactive and found at the bottom of the periodic table.

Alkali Metal: A very reactive metal in Group 1 of the periodic table.

Alkaline Earth Metal: A reactive metal in Group 2 of the periodic table.

Halogen: A very reactive nonmetal in Group 17 of the periodic table.

Inner Transition Element: The lanthanides and actinides, found below the main part of the periodic table.

Lanthanide: A group of 15 elements, often called rare-earth metals, found below the main periodic table.

Noble Gas: A very stable, nonreactive gas in Group 18 of the periodic table.

Representative (Main-Group) Elements: Elements in Groups 1, 2, and 13-18 with a wide range of properties.

Transition Element: Metals in Groups 3-12 that can have different charge states.

Chalcogen: Elements in Group 16, like oxygen and sulfur.

Pnictogen: Elements in Group 15, like nitrogen and phosphorus.

Anion: A negatively charged ion (gains electrons).

Atomic Radius: The size of an atom, from the nucleus to the outermost electron.

Cation: A positively charged ion (loses electrons).

Electron Affinity: The energy change when an atom gains an electron.

Electronegativity: How strongly an atom attracts electrons in a bond.

Ion: An atom or molecule with a charge, from gaining or losing electrons.

Ionization Energy: The energy needed to remove an electron from an atom.

Law of Octaves: The idea that elements' properties repeat every eighth element when sorted by atomic mass.