Atoms and Their Structure

The smallest unit of an element that retains the chemical properties of that element.

A positively charged particle found in the nucleus of an atom.

A neutral particle found in the nucleus of an atom.

The central core of an atom, containing protons and neutrons.

The number of protons in an atom's nucleus.

The total number of protons and neutrons in an atom's nucleus.

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

The collective term for protons and neutrons within the nucleus.

The percentage of a specific isotope of an element found naturally.

The unified atomic mass unit, defined as 1/12th the mass of a carbon-12 atom.

The energy released when a nucleus is formed from its constituent protons and neutrons. It represents the difference between the total mass of the individual nucleons and the mass of the nucleus.

The binding energy per nucleon is a measure of the stability of a nucleus. A higher binding energy per nucleon indicates a more stable nucleus.

The strong nuclear force is a short-range force that binds nucleons together within the nucleus. It is much stronger than the electrostatic repulsion between protons.

The force that acts between quarks, the fundamental particles that make up protons and neutrons. It is responsible for binding the nucleons together in the nucleus.

The short-range nature of the strong nuclear force limits the size of stable nuclei. As the number of protons increases, the electrostatic repulsion becomes stronger, requiring more neutrons to maintain stability.

The strong force is much stronger than the Coulomb force between protons. However, its short-range nature makes it less effective in large nuclei, where the electrostatic forces become dominant.

Radioactivity arises from the disintegration or decay of unstable atoms' nuclei.

Radioactivity is the emission of particles (alpha, beta, gamma) or energy from the nucleus of an atom.

Alpha rays can't penetrate paper, beta rays can go through aluminum, and gamma rays can penetrate lead.

Alpha decay occurs when a nucleus emits an alpha particle (helium nucleus) and releases energy. It's more likely than other decay types because the alpha particle is very stable.

Beta decay occurs when a nucleus emits an electron. The nucleus rearranges its protons and neutrons, resulting in one more proton and one fewer neutron.

This is a nuclear reaction where a nucleus changes its composition by emitting an electron, caused by a force called the weak nuclear force.

In this decay, the emitted electron is not an orbital electron. It's created in the decay process.

Alpha decay is favored compared to other types because alpha particles are highly stable.

The fundamental process of neutron decay, where a neutron transforms into a proton, electron, and neutrino.

A type of beta decay where a nucleus emits a positron, a positively charged antiparticle of electron, alongside a neutrino.

A type of beta decay where a nucleus captures one of its own inner electrons, usually transforming a proton into a neutron.

A type of radioactive decay where a nucleus emits a high-energy photon, causing a transition from an excited state to a lower energy level.

The total number of protons and neutrons (nucleons) in a nucleus, a conserved quantity during radioactive decay, not altered by beta or gamma decay.

A constant describing how quickly a radioactive nuclide decays, determining the rate of decay.

The time it takes for half of the radioactive nuclei in a sample to decay. A characteristic property that defines the decay rate of a specific nuclide.

The time taken for half the nuclei in a given sample to decay. It's related to the decay constant by the formula: T1/2 = ln2 / λ

A series of sequential radioactive decays, where one radioactive isotope decays into another, creating a chain reaction.

A technique used to determine the age of ancient objects, such as fossils or artifacts, by analyzing the ratio of carbon-14 to carbon-12.

The technique of using the known half-life of a radioactive isotope to calculate the age of a sample.

A method for determining the age of geological formations based on the decay of radioactive isotopes, particularly uranium-238.

The activity of a radioactive source changes over time, decreasing exponentially. This decay is characterized by a specific half-life.

The number of radioactive decays per unit time. It's measured in Becquerels (Bq).

A device that detects charged particles by using a gas-filled tube with a central wire at high voltage. When a charged particle passes through, it ionizes the gas, creating a pulse.

A device that detects charged particles by using a scintillator material that emits light when a charged particle passes through it. The light is then amplified by a photomultiplier tube for detection.

A device used to detect charged particles. It contains a supercooled gas or liquid. When a charged particle passes through, droplets (in a cloud chamber) or bubbles (in a bubble chamber) form along its path.

A device that resembles a Geiger counter but is more sophisticated. It uses multiple wires, some at high voltage and some grounded, allowing for precise measurement of particle position based on the time it takes the pulse to reach the wire.