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Unit 2: Atoms
Term | Definition |
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Atomic emission spectrum | The variety of frequencies of electromagnetic radiation (light) seen through a spectroscope that are emitted by electrons as they transition from higher to lower energy levels; unique for each element |
Atomic radius | The number of protons in the nucleus of an atom; the atomic number is the same for all atoms of an element |
Electromagnetic spectrum | All of the frequencies or wavelengths of electromagnetic radiation |
Electronegativity | A measure of the ability of an atom in a chemical compound to attract electrons |
Frequency | The number of cycles or vibrations per unit of time; also the number of waves produced in a given amount of time |
Hyphen notation | A way of designing the isotopes of an element using its name (or symbol), a hyphen, and the mass number (example: uranium-238) |
Ionic radius | A measure of the size of an ion of an element in a crystal |
Ionization energy | The energy required to remove an electron from an atom or ion |
Isotope | An atom that has the same number of protons (or same atomic number) as other atoms of the same element but that has a different number of neutrons (thus a different atomic mass) |
Planck's constant | A constant value that relates the energy of a photon of light to its frequency |
Valence electron | An electron that is found in the outermost shell of an atom and that determines the atom's chemical properties |
Wavelength | The distance from any point on a wave to an identical point on the next wave |