Bill W. Tillery Physical Science Chapter 8
1. Atomic Mass Unit: The relative mass unit (u) of an isotope based on the standard of the carbon-12 isotope, which is
defined as a mass of exactly 12.00 u; one atomic mass unit (1 u) is 1/12 the mass of a carbon-12 atom
2. Atomic Number: The number of protons in the nucleus of an atom
3. Atomic Weight: The weighted average of the masses of stable isotopes of an element as they occur in nature, based on the
abundance of each isotope of the element and the atomic mass of the isotope compared to C-12
4. Electron: A subatomic particle that has the smallest negative charge possible, usually found in an orbital of an atom, but
gained or lost when atoms become ions 5. Electron Dot Notation: A notation made by writing the chemical symbol of an
element with dots around the symbol to indicate the number of outer shell electrons 6. Ion: An atom or a particle that has a
net charge because of the gain or loss of electrons
7. Isotope: Atoms of an element with identical chemical properties but with different masses; different number of
neutrons
8. Mass Number: The sum of the number of protons and neutrons in a nucleus defines the mass number of an atom; used
to identify isotopes
9. Electron Pair: A pair of electrons with different spin quantum numbers that may occupy an orbital
10. Heisenberg Uncertainty Principle: You cannot measure both the exact momentum and the exact position of a
subatomic particle at the same time
11. Neutron: A neutral subatomic particle usually found on the nucleus of an atom
12. 12. Nucleus: The tiny, relatively massive and positively charged center of an atom containing protons and neutrons
13. Proton: The subatomic particle that has the smallest possible charge
14. Representative Elements: The members of the a-group families of the periodic table
15. Semiconductors: Elements that have properties between those of a metal and those of a nonmetal; also called
metalloids
16. Transition Elements: The members of the b-group families of the periodic table
17. 17. Orbital: The region of space around the nucleus of a atom where an electron is likely to be found
18. Pauli Exclusion Principle: No two electrons in an atom can have the same four quantum numbers; thus, a maximum of
two electrons can occupy a given orbital
1. Atomic Mass Unit: The relative mass unit (u) of an isotope based on the standard of the carbon-12 isotope, which is
defined as a mass of exactly 12.00 u; one atomic mass unit (1 u) is 1/12 the mass of a carbon-12 atom
2. Atomic Number: The number of protons in the nucleus of an atom
3. Atomic Weight: The weighted average of the masses of stable isotopes of an element as they occur in nature, based on the
abundance of each isotope of the element and the atomic mass of the isotope compared to C-12
4. Electron: A subatomic particle that has the smallest negative charge possible, usually found in an orbital of an atom, but
gained or lost when atoms become ions 5. Electron Dot Notation: A notation made by writing the chemical symbol of an
element with dots around the symbol to indicate the number of outer shell electrons 6. Ion: An atom or a particle that has a
net charge because of the gain or loss of electrons
7. Isotope: Atoms of an element with identical chemical properties but with different masses; different number of
neutrons
8. Mass Number: The sum of the number of protons and neutrons in a nucleus defines the mass number of an atom; used
to identify isotopes
9. Electron Pair: A pair of electrons with different spin quantum numbers that may occupy an orbital
10. Heisenberg Uncertainty Principle: You cannot measure both the exact momentum and the exact position of a
subatomic particle at the same time
11. Neutron: A neutral subatomic particle usually found on the nucleus of an atom
12. 12. Nucleus: The tiny, relatively massive and positively charged center of an atom containing protons and neutrons
13. Proton: The subatomic particle that has the smallest possible charge
14. Representative Elements: The members of the a-group families of the periodic table
15. Semiconductors: Elements that have properties between those of a metal and those of a nonmetal; also called
metalloids
16. Transition Elements: The members of the b-group families of the periodic table
17. 17. Orbital: The region of space around the nucleus of a atom where an electron is likely to be found
18. Pauli Exclusion Principle: No two electrons in an atom can have the same four quantum numbers; thus, a maximum of
two electrons can occupy a given orbital
