Atoms and the Periodic Table

Front

Atom Noun

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[at-uhm]

Back

Atom

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The basic building block of all matter, representing the smallest unit of an element that retains its chemical properties.

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Example: This diagram shows an atom's structure: a central nucleus with protons and neutrons, and electrons orbiting the nucleus in distinct energy shells or levels.

Front

Proton Noun

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[proh-ton]

Back

Proton

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A positively charged particle found in the center (nucleus) of an atom, which determines the atomic number.

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Example: This diagram shows that protons are particles found inside the central nucleus of an atom, along with neutrons.

Front

Neutron Noun

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[noo-tron]

Back

Neutron

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A particle with no electrical charge, found in the center (nucleus) of an atom, contributing to the atomic mass.

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Example: This diagram shows a neutron (blue sphere) as a particle located inside the atom's central nucleus, along with protons (green spheres) and orbiting electrons (red spheres).

Front

Electron Noun

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[ih-lek-tron]

Back

Electron

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

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Example: This diagram shows electrons (blue dots) as particles that orbit the nucleus of an atom in specific energy shells or layers.

Front

Nucleus Noun

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[noo-klee-uhs]

Back

Nucleus

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The dense, positively charged central part of an atom, containing protons and neutrons and comprising nearly all its mass.

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Example: This diagram shows the nucleus, containing protons and neutrons, at the center of an atom with electrons orbiting it.

Front

Atomic Mass Noun

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[uh-tom-ik mas]

Back

Atomic Mass

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The mass of an atom, calculated as the sum of the protons and neutrons in the nucleus.

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Example: This diagram of a periodic table element tile for Carbon shows that the number at the bottom, 12.01, is the average atomic mass.

Front

Element Noun

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[el-uh-muhnt]

Back

Element

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A pure substance that is made entirely from one type of atom and cannot be broken down by chemical means.

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Example: This diagram shows how an element, like Carbon, is displayed on the periodic table with its atomic number, symbol, name, and atomic mass.

Front

Periodic Table Noun

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

Back

Periodic Table

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A chart displaying all known chemical elements, arranged by atomic number, electron configuration, and recurring chemical properties.

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Example: This chart, the Periodic Table, organizes all known chemical elements by their atomic number, with a key explaining the data shown for each element.

Front

Period Noun

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[peer-ee-uhd]

Back

Period

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The horizontal rows of the periodic table, where elements have the same number of electron shells.

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Example: This diagram shows that a 'period' in the periodic table is a row containing a specific set of elements, using Period 3 as an example.

Front

Group Noun

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[groop]

Back

Group

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The vertical columns of the periodic table, containing elements with similar chemical behaviors and valence electron configurations.

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Example: The periodic table is organized into vertical columns called Groups. Elements in the same group, like the Alkali Metals (purple), share similar chemical properties.