Valence Electrons

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Valence Electrons Noun

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[vay-luhns ih-lek-trons]

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Valence Electrons

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The electrons in the outermost energy level of an atom that are involved in chemical reactions and determine reactivity.

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Atom Noun

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[at-uhm]

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Atom

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The smallest unit of matter that retains all of the chemical properties of a particular chemical element.

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Nucleus Noun

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[noo-klee-uhs]

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Nucleus

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The positively charged central core of an atom, which consists of protons and neutrons and contains most of its mass.

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Energy Level Noun

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[en-er-jee lev-uhl]

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Energy Level

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A fixed region or shell around an atom's nucleus where electrons with a specific amount of energy are found.

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Reactivity Noun

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[ree-ak-tiv-i-tee]

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Reactivity

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The tendency of an atom to participate in chemical reactions, which is largely determined by its number of valence electrons.

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Electron Dot Diagram Noun

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[ih-lek-tron dot dahy-uh-gram]

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Electron Dot Diagram

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A diagram representing an atom's valence electrons as dots surrounding the element's chemical symbol; also called a Lewis Dot Structure.

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Bohr Diagram Noun

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[bohr dahy-uh-gram]

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Bohr Diagram

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A simplified atomic model that depicts electrons orbiting the nucleus in specific, fixed energy levels or shells.

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Periodic Table Noun

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[peer-ee-od-ik tey-buhl]

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Periodic Table

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A chart of the chemical elements, arranged by atomic number, that displays the periodic recurrence of their chemical properties.

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Periods Noun

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[peer-ee-uhds]

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Periods

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The horizontal rows in the periodic table, where all elements within a row have the same number of electron shells.

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Example: This diagram shows the periodic table, where a horizontal row is called a period. Elements in the same period have the same number of electron shells.

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Groups Noun

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[groops]

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Groups

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The vertical columns in the periodic table, where elements have the same number of valence electrons and similar chemical properties.