Nuclear Energy

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Nucleus Noun

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[noo-klee-uhs]

Back

Nucleus

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The central part of an atom, composed of protons and neutrons, containing most of the atom's mass.

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Example: This diagram shows the nucleus at the center of an atom, clearly labeling it as a cluster of protons and neutrons.

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Proton Noun

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[proh-ton]

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Proton

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A subatomic particle with a positive electric charge found within the atomic nucleus that determines an element's atomic number.

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Example: This diagram shows a proton, a subatomic particle, located inside the central nucleus of an atom, along with neutrons and orbiting electrons.

Front

Neutron Noun

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[noo-tron]

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Neutron

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A subatomic particle with no net electric charge found within the atomic nucleus that contributes to an atom's mass.

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Example: This diagram shows that a neutron is a particle located inside the atom's central nucleus, along with protons.

Front

Atomic Number Noun

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[uh-tom-ik nuhm-ber]

Back

Atomic Number

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The number of protons in the nucleus of an atom, which determines the chemical identity of the element.

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Example: This diagram of an Oxygen atom shows 8 protons in its nucleus, which defines its atomic number as 8.

Front

Isotope Noun

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[ahy-suh-tohp]

Back

Isotope

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Atoms of the same element that have the same number of protons but different numbers of neutrons.

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Example: This image shows three carbon atoms. They are isotopes because they all have the same number of protons but a different number of neutrons.

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Mass Number Noun

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[mas nuhm-ber]

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Mass Number

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The total number of protons and neutrons in an atomic nucleus, which determines the mass of an isotope.

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Example: This diagram shows an atom's nucleus, which contains protons (P) and neutrons (N). The mass number is the total count of these two particles.

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Radioactive Decay Noun

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[rey-dee-oh-ak-tiv dih-key]

Back

Radioactive Decay

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The spontaneous process by which an unstable atomic nucleus loses energy by emitting radiation to become more stable.

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Example: This graph shows that as time passes (measured in half-lives), the percentage of a radioactive substance decreases by half for each half-life period.

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Half-life Noun

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[haf-lahyf]

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Half-life

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The time required for half of the radioactive atoms in a given sample to undergo spontaneous radioactive decay.

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Example: This graph shows that for every half-life that passes, the amount of a radioactive substance like Cobalt-60 decreases by exactly half.

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Ionizing Radiation Noun

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[ahy-uh-nahy-zing rey-dee-ey-shuhn]

Back

Ionizing Radiation

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Radiation with sufficient energy to remove electrons from atoms or molecules, thereby creating ions in the process.

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Example: Ionizing radiation is a type of energy that can knock an electron out of an atom, turning the neutral atom into a charged ion.

Front

Alpha Decay Noun

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[al-fuh dih-key]

Back

Alpha Decay

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A type of radioactive decay where an atomic nucleus emits an alpha particle, which consists of two protons and two neutrons.

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Example: An unstable Uranium-235 nucleus releases an alpha particle (two protons and two neutrons) to become a more stable Thorium-231 nucleus.