Introduction to Radioactivity cards week 2 (9/11)

Vocabulary flashcards covering core concepts from Lecture 2 on radioactivity, including nucleus structure, isotopes, decay types, and half-life.

Atomic nucleus

The dense central region of an atom that contains protons and neutrons.

Proton

Positively charged subatomic particle in the nucleus; its number defines the element (atomic number Z).

Neutron

Electrically neutral subatomic particle in the nucleus; contributes to mass and influences isotopes.

Isotope

Atoms of the same element (same Z) with different numbers of neutrons (different mass number A).

Atomic number (Z)

The number of protons in the nucleus; determines the identity of the element.

Mass number (A)

Total number of protons and neutrons in the nucleus.

Nuclear notation (A, Z, X)

Notation showing mass number A, atomic number Z, and chemical symbol X for an isotope.

Parent nucleus

The original nucleus before radioactive decay.

Daughter nucleus

The nucleus formed after radioactive decay.

Radioactive decay

Spontaneous disintegration of an unstable nucleus, emitting particles or radiation.

Alpha decay

Emission of an alpha particle (2 protons and 2 neutrons); daughter nucleus has Z reduced by 2 and A reduced by 4.

Beta decay

Emission of a beta particle; beta-minus increases Z by 1 (A unchanged); beta-plus decreases Z by 1 (A unchanged).

Gamma decay

Emission of a gamma ray; no change in Z or A; daughter nucleus is the same element.

Gamma ray

A high-energy photon emitted during gamma decay.

Half-life

The time required for half of the radioactive nuclei in a sample to decay.

Unstable nucleus

A nucleus that is prone to decay due to an unfavorable balance of protons and neutrons.

Stable nucleus

A nucleus that does not spontaneously decay.

Radioactive isotope

An isotope that is unstable and undergoes radioactive decay.

Nuclear process notation

Symbolic representation of decay processes showing the parent, emitted particles, and the daughter nucleus.

Uranium-238 alpha decay (example)

U-238 emits an alpha particle to become Thorium-234 (example of alpha decay).

Carbon-14 beta decay (example)

C-14 undergoes beta decay to become Nitrogen-14 (example of beta decay).