Unit 3 Vocabulary 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 – a measure of the size on an atom of an element from the nucleus to the outer electrons. Chemical family – a group of elements with similar chemical properties. Electromagnetic spectrum – all of the frequencies of electromagnetic radiation or light. Electronegativity – a chemical property that describes the extent to which an atom attracts electrons towards itself; cannot be directly measured. Frequency –the number of cycles of an event per unit time; one Hertz (Hz) means one cycle per second. Ionic radius – a measure of the size of an ion of an element in a crystal (usually measured by taking half the distance between two nuclei). Ionization energy –a chemical property that describes the amount of energy required to remove an electron from an atom. Isotopes – atoms of an element that have the same atomic number (protons) but different mass numbers due to different numbers of neutrons in their nuclei. Planck’s constant – a constant value that relates the energy of a photon of light to its frequency. Valence electrons – those electrons involved in the formation of chemical bonds. Wavelength –the length between successive peaks (or troughs) of a wave. Unit 3 Vocabulary Atomic emission spectrum Atomic radius Unit 3 Vocabulary Chemical family Electromagnetic spectrum Unit 3 Vocabulary Electronegativity Frequency Unit 3 Vocabulary Ionic radius Ionization energy Unit 3 Vocabulary Isotopes Planck’s constant Unit 3 Vocabulary Valence electrons Wavelength Unit 3 Vocabulary Definition: 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. Unit 3 Vocabulary Definition: a measure of the size on an atom of an element from the nucleus to the outer electrons. Unit 3 Vocabulary Definition: a group of elements with similar chemical properties. Unit 3 Vocabulary Definition: all of the frequencies of electromagnetic radiation or light. Unit 3 Vocabulary Definition: a chemical property that describes the extent to which an atom attracts electrons towards itself; cannot be directly measured. Unit 3 Vocabulary Definition: the number of cycles of an event per unit time; one Hertz (Hz) means one cycle per second. Unit 3 Vocabulary Definition: a measure of the size of an ion of an element in a crystal (usually measured by taking half the distance between two nuclei). Unit 3 Vocabulary Definition: a chemical property that describes the amount of energy required to remove an electron from an atom. Unit 3 Vocabulary Definition: atoms of an element that have the same atomic number (protons) but different mass numbers due to different numbers of neutrons in their nuclei. Unit 3 Vocabulary Definition: a constant value that relates the energy of a photon of light to its frequency. Unit 3 Vocabulary Definition: those electrons involved in the formation of chemical bonds. Unit 3 Vocabulary Definition: the length between successive peaks (or troughs) of a wave. .