MYP Physics Atomic Physics Key Definitions

The smallest unit of an element that retains the element’s chemical properties; it consists of a nucleus (protons and neutrons) with electrons around it.

The ionizing radiation we are exposed to all the time from natural and human-made sources in our environment.

A chain reaction is a self-sustaining sequence of nuclear fission events caused by neutrons released from previous fissions.

A property of matter that can be positive or negative and causes electrical interactions (attraction or repulsion) between objects.

A fundamental particle with a negative electric charge of $-1.6\times 10^{-19}\,\text{C}$ and a very small mass of $9.1\times 10^{-31}\,\text{kg}$.

A force of attraction or repulsion between electric charges.

The half-life of a radioactive substance is the time taken for half of the unstable nuclei in a sample to decay.

An ion is a charged atom formed by the gain or loss of electrons.

Radiation that can remove electrons from atoms or molecules, creating ions.

A mutation is a random change in DNA that introduces new genetic variants (alleles).

A particle in the nucleus with no net charge and a mass about $1.67\times 10^{-27}\,\text{kg}$.

Nuclear fission is the splitting of a heavy atomic nucleus into smaller nuclei, releasing energy and neutrons.

Nuclear waste is unwanted radioactive material produced by nuclear processes.

The plum pudding model describes the atom as a positively charged sphere with negatively charged electrons spread throughout it.

A particle in the nucleus with positive electric charge $+1.6\times 10^{-19}\,\text{C}$ and a mass about $1.67\times 10^{-27}\,\text{kg}$.

Radioactive decay is the process by which an unstable atomic nucleus loses energy by radiation.