Question | Answer |
the highly reactive metallic elements located in Group 1 of the periodic table | alkali metals |
the reactive metallic elements located in Group 2 of the periodic table | alkaline-earth metals |
an ion with a negative charge | anion |
a quantity equal to one-twelfth the mass of a carbon-12 atom | atomic mass unit (amu) |
the number of protons in the nucleus of an atom | atomic number |
the weighted average of the masses of all naturally occurring isotopes of an element | average atomic mass |
the number of particles in 1 mol; equals 6.022 3 × 1023/mol | Avogadro’s constant |
an ion with a positive charge | cation |
a ratio equal to one that expresses the same quantity in two different ways | conversion factor |
a tiny negatively charged subatomic particle moving around outside the nucleus of an atom | electron |
any of the possible energies an electron may have in an atom | energy level |
a vertical column of elements in the periodic table; also called a family | group |
the highly reactive elements located in Group 17 of the periodic table | halogens |
an atom or molecule with a net electric charge due to the loss or gain of one or more electrons | ion |
the process of adding electrons to or removing electrons from an atom or group of atoms | ionization |
any atoms having the same number of protons but different numbers of neutrons | isotopes |
the total number of protons and neutrons in the nucleus of an atom | mass number |
the elements that are good conductors of heat and electricity | metals |
the mass in grams of 1 mol of a substance | molar mass |
the SI base unit that describes the amount of a substance | mole |
a neutral subatomic particle in the nucleus of an atom | neutron |
the unreactive gaseous elements located in Group 18 of the periodic table | noble gases |
the elements that are usually poor conductors of heat and electricity | nonmetals |
the center of an atom; made up of protons and neutrons | nucleus |
a region in an atom where there is a high probability of finding electrons | orbital |
a horizontal row of elements in the periodic table | period |
the properties of elements tend to repeat in a regular pattern when elements are arranged in order of increasing atomic number | periodic law |
a positively charged subatomic particle in the nucleus of an atom | proton |
the elements that are intermediate conductors of heat and electricity | semiconductors |
the metallic elements located in Groups 3–12 of the periodic table | transition metals |
an electron in the outermost energy level of an atom | valence electron |