periodic law
the law that states that the repeating chemical and physical properties of elements change periodically with the atomic numbers of the elements
period
A horizontal row of elements in the periodic table
group
Vertical column in the periodic table
metal
A class of elements characterized by physical properties that include shininess, malleability, ductility, and conductivity.
Nonmetals
Elements that are poor conductors of heat and electric current
Metalloid
An element that has some characteristics of both metals and nonmetals
Akali Metals
Group 1A, excluding Hydrogen. Highly reactive.
akaline earth metals
Metals with two valance electrons, found in Group 2A
transition metals
Groups 3-12, 1-2 electrons in the outer energy level, less reactive than alsali-earth metals, shiny, good conductor of thermal energy and electrical current, high density
halogen
An element found in group 17 of the periodic table
noble gas
Elements in group 8A of the periodic table. Have no charge and are gases under normal conditions. (Helium, Neon, Argon, Krypton, Xenon, Radon)
Octet
States that atoms lose, gain or share electrons in order to acquire a full set of eight valence electrons
atomic radius
one-half the distance between the nuclei of identical atoms that are bonded together
ionic radius
Distance from the center of an ion's nucleus to its outermost electron
Electronegativity
the ability of an atom to attract electrons when the atom is in a compound
ionization energy
The amount of energy required to remove an electron from an atom