The actinides comprise elements 89 through 103. They, along with the actinides, are often called the f-elements because they have valence electrons in the f shell.
The alkali metals make up the first column (group) of the periodic table, and comprise Li through Fr.
The alkaline earth metals make up the second column (group) of the periodic table, from Be through Ra.
The atomic number is the number of protons in an atomic nucleus.
Atomic orbitals are regions of space around the nucleus of an atom where an electron is most likely to be found.
The atomic radius is the total distance from an atom's nucleus to the outermost electron orbital.
The atomic weight is the average mass of an atom of an element.
A chemical symbol is a notation of one or two letters representing a chemical element.
A material that conducts heat or electricity, which means electrons can easily flow through the object.
A complex consisting of two atoms.
The d-block is the section of elements on the periodic table in groups 3 – 12.
Electron affinity is the amount of energy absorbed when an electron is added to an atom.
Electronegativity is a measure of the attraction an atom has for electrons.
An element is a substance composed of atoms with identical atomic number.
Exothermic is the term used to describe a reaction that releases heat.
The f-block is the section of elements below the main section of the periodic table consisting of the lanthanide and actinide elements.
A taxon (group of organisms) made up of related genera.
A flame test is a test for detecting the presence of certain metals by determining the color they emit when put in a flame.
A group is also called a family. It is a column of elements in the periodic table that all have similar properties.
The halogen elements are a subset of the nonmetals. They comprise group 17 of the periodic table, from F through At.
The ionization energy is the energy needed to remove an electron from an atom.
The lanthanides comprise elements 57 through 71. Along with the actinides they are often called the f-elements because they have valence electrons in the f shell.
Groups 1-2 and 13-18 are called the main-group elements.
Malleability means an object is capable of being hammered into sheets or shapes.
Metalloids are also called semi-metals. They are the elements B, Si, Ge, As, Sb, Te, and Po.
A metal is a substance that conducts heat and electricity, is shiny, and can be hammered into sheets or drawn into a wire.
The noble gases comprise group 18. They are generally very stable, colorless, and odorless.
The term non-metals is used to classify the elements H, C, N, P, O, S, and Se.
The oxidation state is the charge associated with an atom.
An oxide is a compound composed of a metal and oxygen.
The p-block is the section of the periodic table composed of the last six groups or columns.
A period is a horizontal row of the periodic table.
The periodic law is the principle that the properties or characteristics of the elements recur periodically as their atomic numbers increase.
The s-block is the section of elements on the periodic table composed of the first two groups or columns.
The transition elements are metals that have a partially filled d subshell and comprise groups 3 through 12 and the lanthanides and actinides.
Valence electrons are the electrons of an atom that are highest in energy and in the outermost orbitals.