Download Elements and the Periodic Table Section One

Science Explorer- Chemical Building Blocks
Chapter Three- Elements and the Periodic Table
Section One
Atomic Mass: the average mass of one atom of an element (pg. 77)
Periodic Table: a chart of the elements showing the repeating pattern of their properties (pg.
78)
Nucleus: the central core of an atom containing protons and usually neutrons (pg. 79)
Proton: a small, positively charged particle in the nucleus of the atom (pg. 79)
Neutron: a small particle in the nucleus of the atom, with no electrical charge (pg. 79)
Electron: a tiny, negatively charged particle that moves around the nucleus of an atom (pg.
79)
Atomic Mass Unit (amu): a unit used to measure the mass of particles in atoms; a proton or
neutron has a mass of 1 amu (pg. 79)
Atomic Number: the number of protons in the nucleus of an atom (pg. 79)
Chemical Symbol: a one- or two- letter representation of an element (pg. 82)
Family: elements in the same vertical column of the periodic table; also called group (pg. 82)
Group: elements in the same vertical column of the periodic table; also called family (pg. 82)
Period: a horizontal row of elements in the periodic table (pg. 83)
Valence Electron: one of the electrons farthest away from the nucleus of the atom; these
electrons are involved in a chemical reaction (pg. 85)
Section Two
Malleable: a term used to describe material that can be hammered or rolled into shape (pg.
87)
Ductile: a term used to describe a material that can be pulled out into a long wire (pg. 87)
Conductor: a substance that transmits heat or electricity easily (pg. 88)
Magnetic: a characteristic of those metals that are attracted to magnets and can be made
into magnets (pg. 88)
Reactivity: the ease and speed with which an element or compound combines with other
elements and compounds (pg. 88)
Corrosion: the gradual wearing away of a metal element due to a chemical reaction (pg. 88)
Alloy: a mixture of two or more metals (pg. 89)
Alkali Metals: an element in Group 1 of the periodic table (pg. 89)
Transition Metals: an element in Group 3 through 12 of the periodic table (pg. 90)
Lanthanide: an element in the first row of the rare earth elements in the periodic table (pg.
92)
Actinides: an element in the second row of the rare earth elements in the periodic table (pg.
92)
Section Three
Nonmetals: an element that lacks most of the properties of metals (pg. 96)
Diatomic Molecule: a molecule composed of two atoms (pg. 97)
Halogen Family: the elements in Group 17 of the periodic table (pg. 100)
Metalloid: an element that has some of the characteristics of metals and some of the
characteristics of nonmetals (pg. 101)
Semiconductor: an element that can conduct electricity under some conditions (pg. 101)
Section Four
Plasma: a state of matter in which atoms are stripped of their electrons and the nuclei
packed closely together (pg. 104)
Nuclear Fusion: the process in which smaller nuclei combine into larger nuclei, forming
heavier elements (pg. 105)
Supernova: an explosion of a massive star (pg. 106)