Atomic Radius

Front

Atomic Radius Noun

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[uh-tom-ik rey-dee-uhs]

Back

Atomic Radius

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A measure of an atom's size, defined as half the distance between the nuclei of two identical, touching atoms.

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Example: The atomic radius is defined as half the distance between the nuclei of two identical atoms that are bonded together.

Front

Nuclear Charge Noun

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[noo-klee-er chahrj]

Back

Nuclear Charge

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The total positive charge of an atom's nucleus, which is determined by the number of protons it contains.

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Example: The image shows the nucleus containing positively charged protons. The total positive charge from all the protons in the nucleus is the nuclear charge.

Front

Shielding Effect Noun

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[sheeld-ing ih-fekt]

Back

Shielding Effect

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The reduction in the attractive force between the nucleus and outer electrons due to the blocking effect of inner electrons.

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Example: Inner-shell electrons reduce the positive nucleus's pull on an outer-shell electron, effectively 'shielding' it and weakening its attraction to the atom's center.

Front

Energy Level Noun

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[en-er-jee lev-uhl]

Back

Energy Level

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A specific region around an atom's nucleus where an electron is most likely to be found, also known as an electron shell.

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Example: This diagram shows a Sodium atom with its electrons arranged in three distinct energy levels, or shells, around the central nucleus.

Front

Period Noun

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[peer-ee-uhd]

Back

Period

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A horizontal row in the periodic table, where elements have the same number of occupied principal energy levels.

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Example: This diagram shows that periods are the horizontal rows on the periodic table.

Front

Group Noun

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[groop]

Back

Group

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A vertical column in the periodic table, where elements typically have similar chemical properties and electron configurations.

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Example: This image shows that groups are the vertical columns on the periodic table, with specific groups like Alkali Metals (Group 1) and Halogens (Group 17) labeled.

Front

Electron Cloud Noun

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[ih-lek-tron kloud]

Back

Electron Cloud

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The region of negative charge surrounding an atomic nucleus that is associated with an atomic orbital where electrons are located.

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Example: This diagram shows an atom's central nucleus surrounded by electrons moving in a large space, the electron cloud, whose size determines the atomic radius.

Front

Nucleus Noun

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[noo-klee-uhs]

Back

Nucleus

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The small, dense, positively charged center of an atom, which is composed of protons and neutrons.

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Example: This diagram shows the atom's central nucleus, which contains protons and neutrons, with electrons orbiting it, establishing the core structure of an atom.

Front

Inner Electrons Noun

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[in-er ih-lek-trons]

Back

Inner Electrons

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Electrons that are not in the outermost energy level of an atom and are responsible for the shielding effect.

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Example: This diagram of a carbon atom shows that inner electrons, also called core electrons, are located in the electron shells closer to the nucleus.

Front

Outer Electrons Noun

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[ou-ter ih-lek-trons]

Back

Outer Electrons

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Electrons located in the highest occupied energy level of an atom, also known as valence electrons, which determine size.

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Example: This diagram of an oxygen atom shows the electrons in the outermost energy shell, which are called the outer or valence electrons.