Chapter 12 Vocabulary

3. A representation of an object on some con- venient scale.
8. A small, discrete packet of light energy.
9. Members of a set of atoms of the same element whose nuclei contain the same number of protons but different numbers of neutrons.
13. A count of the number of protons in the atomic nucleus.
16. An extremely small negatively charged subatomic particle found outside the atomic nucleus.
17. The abbreviation for an element or atom.
18. Any material that is made up of only one type of atom.
19. n An integer that specifies the quantized energy level of an atomic orbital.
21. in order of atomic number.
22. Any subatomic particle found in the atomic nucleus; another name for either a proton or a neutron.

1. The pattern of frequencies of electromagnetic radiation emitted by the atoms of an element, considered to be an element’s “fingerprint."
2. The idea that light energy is contained in discrete packets called quanta.
4. A device that uses a prism or diffraction grat- ing to separate light into its color components.
5. A vertical column in the periodic table also known as
6. A representation of a system that helps us predict how the system behaves.
7. A chart in which all the known elements are
10. The mass of an element’s atoms listed in the periodic table as an average value based on the relative abundance of the element’s isotopes.
11. A region of space around the atomic nucleus within which electrons may reside.
12. A horizontal row in the periodic table
14. The dense, positively charged center of every atom.
15. An electrically neutral subatomic particle of the atomic nucleus.
20. A positively charged subatomic particle of the atomic nucleus.