physics unit 10

Atom

The smallest unit of an element that displays the characteristic properties of that element.

Nucleus

The dense central core of an atom, made up of protons and neutrons.

Proton

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

Neutron

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

Electron

A negatively charged particle that orbits the nucleus of an atom.

Ground State

The lowest possible energy arrangement of electrons in an atom.

Isotope

An atom with the same number of protons but different numbers of neutrons in its nucleus.

Mass Number

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

Atomic Number

The number of protons in the nucleus of an atom, which defines the element.

Stable Isotope

An isotope with a nucleus that does not decay over time.

Radioisotope

An unstable isotope that decays over time, emitting radiation.

Alpha Decay

A type of radioactive decay in which an alpha particle (2 protons and 2 neutrons) is emitted from the nucleus.

Beta Decay

A type of radioactive decay in which a neutron is converted to a proton and an electron is emitted.

Gamma Decay

A type of radioactive decay that involves the emission of gamma rays, with no change in atomic mass or number.

Nuclear Fission

A process where heavy atomic nuclei split into lighter nuclei, releasing a large amount of energy.

Nuclear Fusion

A process where light atomic nuclei combine to form a heavier nucleus, releasing energy.

Half-life

The amount of time it takes for half of the isotopes in a sample to decay.

Quantum Model

A model of the atom where electrons are treated as matter waves and exist in probabilistic states around the nucleus.

Photoelectric Effect

The emission of electrons from a material when light of certain frequencies shines on its surface.

Wave-Particle Duality

The concept that particles such as electrons exhibit both wave and particle properties.

Heisenberg Uncertainty Principle

The principle stating that it is impossible to simultaneously know the exact position and momentum of a particle.

Planck's Constant

A fundamental constant (h) used in quantum mechanics to describe the quantization of energy.

Absorption Spectrum

A spectrum showing dark lines where specific wavelengths of light have been absorbed by an atom.

Emission Spectrum

A spectrum showing bright lines where specific wavelengths of light have been emitted by an atom.

Quark

A fundamental particle and a basic constituent of matter, making up protons and neutrons.

Strong Nuclear Force

The force that holds protons and neutrons together in the atomic nucleus.

Weak Nuclear Force

The force responsible for radioactive decay and other neutrino interactions.