Pathway 4: Chapter 4 Vocabulary                          Answers

1. Atomic Mass  The total mass of an atom. The atomic mass of each element presented in the periodic table is the average atomic mass of the various isotopes of that element occurring in nature.

2. Atomic Nucleus  The dense, positively charged center of every atom.

3. Atomic Number  The number of protons in the atomic nucleus of each atom of a given element.

4. Atomic Spectrum The pattern of frequencies of electromagnetic radiation emitted by the atoms of an element, considered to be an element’s “fingerprint.”

5. Conceptual Model A representation of a system that helps us predict how the system behaves.

6. Effective Nuclear Charge The nuclear charge experienced by outer-shell electrons, diminished by the shielding effect of inner-shell electrons and also by the distance from the nucleus.

7. Electromagnetic Spectrum The complete range of waves, from radio waves to gamma rays.

8. Electron  An extremely small, negatively charged subatomic particle found outside the atomic nucleus.

9. Electron Configuration The arrangement of an atom’s electrons within orbitals.

10. Energy-level diagram A schematic drawing used to arrange atomic orbitals in order of increasing energy levels.

11. Inner-Shell Shielding The tendency of inner-shell electrons to partially shield outer-shell electrons from the attractive pull exerted by the positively charged nucleus.

12. Ionization Energy The amount of energy needed to pull an electron away from an atom.

13. Isotope  Any member of a set of atoms of the same element whose nuclei contain the same number of protons but different numbers of neutrons.

14. Mass Number  The number of nucleons (protons plus neutrons) in the atomic nucleus. Used primarily to identify isotopes.

15. Neutron  An electrically neutral subatomic particle found in atomic nuclei.

16.  Nucleon  Any subatomic particle found in an atomic nucleus. Another name for either proton or neutron.

17.Physical Model A representation of an object on some convenient scale.

18. Proton  A positively charged subatomic particle in atomic nuclei.

19. Quantum A small, discrete packet of energy.

20. Quantum Number  An integer that specifies the quantized energy level within an atom.

21. Shell A graphic representation of a collection of orbitals of comparable energy in a multielectron atom. A shell can also be viewed as a region of space about the atomic nucleus within which electrons may reside.

22. Spectroscope A device that uses a prism or diffraction grating to separate light into its color components and measure their frequencies.