Element Symbol Words
Average mass of an element’s isotopes, weighted according to the abundance of each isotope
Average Atomic Mass
smallest piece of an element that still represents the element
Atom
process that occurs when an unstable atomic nucleus changes into another more stable nucleus by emitting radiation
Nuclear Decay
ability of a metal to reflect light
Luster
element in group 17 on the periodic table
Halogen
sum of the number of protons and neutrons in an atom
Mass Number
atomic particle with one negative charge (1–)
electron
any of two or more atoms of the same element that have different numbers of neutrons
Isotope
ability of a substance to be pulled into thin wires
Ductility
element with physical and chemical properties of metals and nonmetals
Metalloid
the number of protons in an atom of an element
Atomic Number
area around an atomic nucleus where an electron is most likely to be found
Electron Cloud
atom that is no longer neutral because it has gained or lost electrons
Ion
ability of a substance to be hammered or rolled into sheets
Malleability
element in group 18 on the periodic table
Noble Gas
column on the periodic table
Group
neutral particle in the nucleus of an atom
Neutron
describes elements that spontaneously emit radiation
Radioactivce
element in group 1 on the periodic table
Alkali metal
material that conducts electricity at high temperatures but not at low temperatures
Semiconductor
row on the periodic table
Period
small area in the center of an atom in which most of an atom’s mass and positive charge is concentrated
Nucleus
to make by combining and arranging parts
Construct
element in group 2 on the periodic table
Alkaline earth metal
element in groups 3–12 on the periodic table
Transition element