Elements for Kids
- Symbol: Ra
- Atomic Number: 88
- Atomic Weight: 226
- Classification: Alkaline earth metal
- Phase at Room Temperature: Solid
- Density: 5.5 grams per cm cubed
- Melting Point: 700°C, 1292°F
- Boiling Point: 1140°C, 2084°F
- Discovered by: Marie and Pierre Curie in 1898
Radium is the sixth element of the second column in the periodic table. It is the heaviest of the alkaline earth metals
. Radium atoms have 88 electrons and 88 protons with 2 valence electrons in the outer shell.
Characteristics and Properties
Under standard conditions radium is a silvery metal. It is very radioactive
emitting light rays that cause it to glow in the dark. When exposed to the air it will quickly form a black coating by reacting with the nitrogen in the air. It also reacts readily with other elements and substances including water.
The radiation given off by radium is extremely dangerous. It is over one million times as radioactive as uranium. Overexposure to radium can cause cancer and eventually death. Marie Curie
, one of the original scientists who worked with radium, eventually died of overexposure to radiation.
Where is it found on Earth?
Radium is an extremely rare element on Earth. It is found in uranium ores. It takes about 7 tons of ore just to produce a single gram of radium. It is produced as a byproduct of uranium mining. Because it is so dangerous, only a few ounces are produced each year.
How is radium used today?
When radium was first discovered it had a number of uses. It was used in paints that would glow. These paints were used on clocks, watches, and instruments so people could see them in the dark. Other uses included cancer treatment, toothpaste, and research experiments.
Today radium does not have any major industrial uses due to the danger of its radioactivity.
How was it discovered?
Marie Curie and her husband Pierre discovered the element while experimenting with the mineral called pitchblende in 1898. It took another 12 years for Marie Curie to finally isolate metallic radium in 1910.
Where did radium get its name?
The name comes from the Latin word "radius" which means ray. They named it after the rays that were emitted from the element.
There are four naturally occurring isotopes of radium. The most abundant is radium-226 which has a half-life of 1600 years. None of the isotopes are stable. They are all produced by the decay of the elements uranium and thorium.
Interesting Facts about Radium
More on the Elements and the Periodic Table
More Chemistry Subjects
- The element "curium" is named for the discoverers of radium.
- Marie Curie also discovered the element polonium while experimenting with pitchblende.
- Before the dangers of radiation were understood, radium was called the wonder metal because it gave off heat and light.
- Radium is part of a decay chain where it will slowly decay into radon, then polonium, and finally lead.
- The unit for measuring radioactivity is called the "curie" after scientists Marie and Pierre Curie.