elements in Group 2A of the periodic table; the ions of the elements in this group have 2+ charge

the electrode at which oxidation occurs; it is the positively charged electrode within a cathode ray tube

the smallest particle of an element that retains the chemical identity of the element; made up of positively charged protons, negatively charged electrons, and neutrons

the weighted average of the masses of the existing isotopes of an element; the sum of the masses of an element’s isotopes each multiplied by its natural abundance

the number of protons in the nucleus of an atom

the electrode at which reduction occurs; it is the negatively charged electrode within a cathode ray tube

a stream of electrons produced at the negative electrode (cathode) of a tube containing a gas at low pressure

elements that exist as diatomic molecules in nature; they include oxygen, hydrogen, nitrogen, fluorine, chlorine, iodine, and bromine

a negatively charged particle within an atom; it has a mass of 0.000549 amu

an electron that has absorbed energy and, therefore, exists at a higher energy level

the normal state of an electron or atom; at this state the electron or atom has the lowest possible energy

a vertical column on the periodic table with similar electron configurations, chemical properties, and the same number of valence electrons

elements in Group 7A (17); they are the most reactive nonmetals

an atom that has the same number of protons as another, identical atom, but with differing numbers of neutrons

the sum of the number of protons and neutrons in the nucleus of an atom

an element that typically has a high melting point, is ductile, malleable, and shiny, and a good conductor of heat and electricity

elements found on the stair-step line of the periodic table with properties of metals and nonmetals

a neutral particle within the nucleus of an atom; it has a mass of 1.00867 amu

elements in Group 8A (18); they do not readily react with other elements due to a satisfied octet; they are inert

elements that typically have a low melting point,a dull surface, breaks easily, and is a poor conductor of heat and electricity

a horizontal row on the periodic table; the elements within the same period have the same number of energy levels

natural law that states that the chemical and physical properties of elements are periodic functions of their atomic numbers

an arrangement of the elements by their atomic numbers so that elements are periodic functions of their atomic numbers

a positively charged particle within the nucleus of an atom; it has a mass of 1.00720 amu

the percentage of an isotope that occurs in nature

the attractive force among the particles in the nucleus of an atom; in a stable atom, it overcomes the forces of repulsion among protons

elements found in the middle column of the periodic table; they have multiple oxidation states

electrons in the outermost energy level of an atom

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