Download Periodic Table Vocab page 7

Periodic Table Vocab
page 8
Atomic number: the number of protons in the nucleus of an atom. This number
identifies the atom.
Mass number: the number of protons and neutrons in the nucleus of an atom.
Mass number = protons + neutrons
Valence #: The number of outermost electrons in an atom.
Periodic Table: An arrangement of elements in order of increasing atomic
numbers that demonstrates the periodic patterns that occur among the
elements.
Period: Elements in a horizontal row on the periodic table
Group: Elements in a vertical column on the periodic table; also called a family
Metal: An element below and to the left of the stair-step line of metalloids; about
80% of the known elements are metals.
Nonmetal: An element above and to the right of the stair-step line of metalloids.
Metalloid: An element with properties of both metals and nonmetals located
along the stair-step line on the right side of the periodic table.