Sodium

Sodium

Sodium is a chemical element with the symbol Na and atomic number 11. It is a soft, silvery-white, highly reactive metal and is a member of the alkali metals; its only stable isotope is 23Na. It is an abundant element that exists in numerous minerals, most commonly as sodium chloride...

-24 (²⁴Na) is one of the more important isotopes of sodium

Isotopes of sodium

There are twenty recognized isotopes of sodium ranging from 18Na to 37Na and two isomers . 23Na is the only stable isotope. As such, it is considered a monoisotopic element and it has a standard atomic mass: 22.98976928 u. Sodium has two radioactive cosmogenic isotopes...

. It is radioactive and created from common sodium-23 by neutron

Neutron

The neutron is a subatomic hadron particle which has the symbol or , no net electric charge and a mass slightly larger than that of a proton. With the exception of hydrogen, nuclei of atoms consist of protons and neutrons, which are therefore collectively referred to as nucleons. The number of...

 bombardment. With a 15-hour half-life

Half-life

Half-life, abbreviated t½, is the period of time it takes for the amount of a substance undergoing decay to decrease by half. The name was originally used to describe a characteristic of unstable atoms , but it may apply to any quantity which follows a set-rate decay.The original term, dating to...

, ²⁴Na decays to ²⁴Mg

Isotopes of magnesium

Magnesium naturally occurs in three stable isotopes, 24Mg, 25Mg, and 26Mg. 19 radioisotopes have been discovered, ranging from 19Mg to 40Mg. The longest-lived radioisotope is 28Mg with a half-life of 20.915 hours. The lighter isotopes mostly decay to isotopes of sodium while the heavier isotopes...

 by emission of an electron

Electron

The electron is a subatomic particle with a negative elementary electric charge. It has no known components or substructure; in other words, it is generally thought to be an elementary particle. An electron has a mass that is approximately 1/1836 that of the proton...

 and two gamma ray

Gamma ray

Gamma radiation, also known as gamma rays or hyphenated as gamma-rays and denoted as γ, is electromagnetic radiation of high frequency . Gamma rays are usually naturally produced on Earth by decay of high energy states in atomic nuclei...

s. Exposure of the human body to intense neutron flux creates ²⁴Na in blood plasma

Blood plasma

Blood plasma is the straw-colored liquid component of blood in which the blood cells in whole blood are normally suspended. It makes up about 55% of the total blood volume. It is the intravascular fluid part of extracellular fluid...

. Measurements of its quantity are used to determine the absorbed radiation dose of the patient. This is used to determine the level of medical treatment required.

When the sodium potassium alloy NaK

NaK

NaK, or sodium-potassium alloy, an alloy, of potassium , and sodium , is usually liquid at room temperature. Various commercial grades are available. NaK is highly reactive with water and may catch fire when exposed to air, so must be handled with special precautions...

 is used as a coolant in nuclear reactors, ²⁴Na is created, which makes the coolant radioactive. When the ²⁴Na decays, it causes a buildup of magnesium in the coolant. Since the half-life is short, the ²⁴Na portion of the coolant ceases to be radioactive within a few days after removal from the reactor.