Ra Element

Radium is a type of chemical element that has the symbol Ra and an atomic number of 88. It is the sixth element in the group 2 of the periodic table, also called the alkaline earth metals. Pure radium is silvery-white in colour, however, it readily reacts with nitrogen rather than oxygen when exposed to air, and forms a black surface layer of radium nitride.  All of the isotopes of radium are highly radioactive and the most stable isotope is radium-226 that has a half-life of 1600 years and decays into radon gas (specifically the isotope called radon-222). When the element radium decays, it yields ionizing radiation as a product that can excite the fluorescent chemicals and cause radioluminescence. In this article, we will learn about radium, the Ra element in detail, the use of radium, radium properties, the radium electronic configuration, and the effects of radium.

What is Radium?

Radium is a type of chemical element with a symbol Ra. It is the sixth element that lies in the group 2 of the periodic table. Pure form of radium is silvery-white in colour, however, it combines with nitrogen readily when it is exposed to air and forms a black surface layer of the radium nitride. Radium was discovered in the year 1898 by Marie Sklodowska Curie and Perre Curie in the form of radium chloride. They had extracted the radium compound from the element called uraninite. It is found in the uranium ores at the concentration of 1 part per 3 million parts uranium.

Physical Properties of Radium

Let us now look at the physical properties of radium.

Radium is known to be the heaviest known alkaline earth metal and is the one and only radioactive member of its periodic group. Its physical and chemical properties are much closely similar to its lighter congener which is barium.

Radium is a highly reactive metal to be known and it always exhibits its group oxidation state. It has the tendency to form the colourless Ra²⁺ cation in aqueous solution, which is highly basic in nature and does not form any complexes. Most of the radium compounds are for this reason simple ionic compounds.

Radium emits the alpha rays, beta rays, and gamma rays when it is mixed with the beryllium produces neutrons.

Let us now take a look at some of the chemical properties of radium.

Chemical Properties of Radium

Radium symbol


Atomic number of radium


Radium atomic mass

226 g/mol

Group of radium


Period of radium


Block of radium


State of radium at 20°C


Electronic configuration of radium


Melting point of radium

696°C or 1285°F or 969 K

Boiling point of radium

1500°C or 2732°F or 1773 K

Density of radium

5 g/cm³

Relative atomic mass of radium


Key isotopes of radium


Who found radium

Marie Sklodowska Curie and Perre Curie in the year1898

Radium Uses

Let us now take a look at what can radium be used for and see some of its applications.

  1. Some of the practical uses of radium are due to its radioactive properties. Radium was previously used in the self-luminous paints for watches, aircraft switches, nuclear panels clocks, and instrument dials.

  2. Ra was earlier used as an additive in the products like hair cream, toothpaste, and even food items.

  3. Radium was also used in the field of medicine for producing radon gas that in turn was used as a cancer treatment.

Health Effects of Radium

Now that you know about radium, let us see how radium is harmful to the health of the humans.

Radium is highly radiotoxic and carcinogen when it is inhaled, ingested or exposed and when it is used in the treatment of cancer and several other body disorders. The Ra element is more than a million times more radioactive than the same mass as that of uranium.

FAQ (Frequently Asked Questions)

1. What is the Number of Neutrons in Radium?

The nucleus of radium consists of 88 protons and 138 neutrons. 88 electrons successively occupy the available electron shells. Radium is a radioactive alkaline earth metal that is present in group 2, period 7, and the s-block of the periodic table.

2. What is Radium Reactivity?

Radium is the heaviest known and most reactive element amongst the alkaline earth metals family. Radium is the rarest because of its high reactivity and its short half-life. It is a part of the group of the elements which appear after bismuth (Z=83) that are all radioactive and unstable in nature. As uranium decays it slowly turns into the element radium and eventually turns into the stable lead.

3. Where is Radium Found?

In the environment, radium is found in uranium and to a lesser extent is found in the thorium ores in trace amounts as small as a seventh of a gram per ton of uraninite. Radium is not required for the living organisms, and adverse health effects are likely to happen when it is incorporated into biochemical processes due to its radioactivity and chemical reactivity. Currently, other than its use in the nuclear medicine, radium has no commercial applications. However, formerly, it was used as the radioactive source in the radioluminescent devices and also in the radioactive quackery for its supposed curative powers. Today, these former applications are no longer in use since the radium's toxicity has become known, and less dangerous isotopes are used instead of radium in the radioluminescent devices.