The Periodic Table and Atomic Structure

Front

Periodic Table Noun

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[peer-ee-od-ik tay-bull]

Back

Periodic Table

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A chart that organizes chemical elements by atomic number, electron configuration, and recurring chemical properties, revealing periodic trends.

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Example: This chart, the periodic table, organizes all known chemical elements in rows (periods) and columns (groups) based on their atomic number and shared chemical properties.

Front

Atomic Number Noun

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[uh-tom-ik num-ber]

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Atomic Number

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The number of protons in an atom's nucleus, which uniquely identifies a chemical element and is symbolized as Z.

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Example: This diagram shows that the atomic number of an element is determined by counting the number of protons (green spheres) in the atom's nucleus.

Front

Nucleus Noun

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[noo-klee-us]

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Nucleus

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The positively charged central core of an atom, composed of protons and neutrons, and containing nearly all its mass.

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Example: This diagram shows the atom's central nucleus, which contains protons and neutrons, with electrons orbiting around it.

Front

Electron Noun

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[eh-lek-tron]

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Electron

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A stable, negatively charged subatomic particle that orbits the nucleus of an atom in specific energy levels or shells.

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Example: This diagram shows an electron as a negatively charged particle that orbits the nucleus of an atom in specific energy levels or shells.

Front

Proton Noun

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[pro-ton]

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Proton

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A stable, positively charged subatomic particle located within the nucleus of every atom, defining the atomic number.

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Example: This diagram shows that a proton is a particle with a positive charge (+) located inside the central nucleus of an atom.

Front

Electron Configuration Noun

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[eh-lek-tron con-fig-yur-ay-shun]

Back

Electron Configuration

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The specific arrangement and distribution of electrons in the orbitals or shells surrounding the nucleus of an atom.

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Example: This Bohr model shows how electrons are arranged in shells around an atom's nucleus. The numbers 2, 8, 1 represent the electron configuration for Sodium.

Front

Group (Periodic Table) Noun

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[groop]

Back

Group (Periodic Table)

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A vertical column in the periodic table containing elements with similar valence electron configurations and chemical properties.

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Example: This image shows the periodic table with a red box highlighting a vertical column, which is called a group. Elements in the same group have similar chemical properties.

Front

Period (Periodic Table) Noun

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[peer-ee-ud]

Back

Period (Periodic Table)

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A horizontal row in the periodic table where all elements have the same number of principal electron shells.

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Example: This image highlights a single horizontal row, Period 3, on the periodic table, showing that a period consists of elements arranged in a line.

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s-block Noun

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[ess-blok]

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s-block

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The region of the periodic table, including Groups 1 and 2, where the highest-energy electron occupies an s-orbital.

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Example: This diagram shows the periodic table divided into colored sections. The light green section, labeled 's block,' includes the first two columns of elements.

Front

p-block Noun

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[pee-blok]

Back

p-block

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The region of the periodic table, including Groups 13 to 18, where the highest-energy electron occupies a p-orbital.

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Example: This diagram shows the periodic table divided into blocks, with the p-block highlighted in orange on the right side, containing groups 3A through 8A.