Which lanthanide is radioactive

There are special laboratories across the world that specialize in experimenting on elements. Some of these particle accelerators have pounded atomic particles into elements with lower atomic numbers. The buildup of additional parts creates short-lived, high atomic number elements.

Meet the Family The actinide family is comprised of fifteen elements that start with actinium Ac at atomic number 89 and finish up with lawrencium Lr at number It's doubtful your teachers will ever ask you to remember all of the elements in the series. You have probably heard of plutonium Pu , since it was used in atomic bombs.

Uranium U is also well known for its radioactivity. The 14 elements numbers 58 to 71 of the lanthanide series are also known as the rare earth elements. Most lanthanides are formed when uranium and plutonium undergo nuclear reactions. Atomic bombs charged with plutonium actinoid were used in World War II.

Plutonium was a power source for Voyager spacecrafts launched in and is also used in artificial heart pacemakers. The f sublevel contains seven orbitals, each of which will hold two electrons. Therefore, it is possible to place 14 electrons in the 4f sublevel. Generally speaking, the lanthanides have electron configurations that follow the Aufbau rule, and the 4f sublevel is filled as atomic number increases from cerium Ce to lutetium Lu. However, there are three lanthanide metals that have properties similar to the d block: cerium Ce , lutetium Lu , and gadolinium Gd.

All of these metals contain a d electron in their electron configuration. A similar overall trend holds for the 14 elements in the actinide series numbers 90 to : from thorium Th to Lawrencium Lr , the 5f sublevel is progressively filled. The chemistry of the lanthanides differs from main group elements and transition metals because of the nature of the 4f orbitals.

As a consequence, the chemistry of the elements is largely determined by their size, which decreases gradually with increasing atomic number. This phenomenon is known as the lanthanide contraction. Actinides are typical metals. The chemical symbol for promethium is Pm. It is a radioactive metal found in the lanthanide series on the periodic table, a group of metallic elements. All of its isotopes are radioactive.

The colour of lanthanide ions is due to the presence of partly filled f orbitals. As a result it is possible to absorb certain wavelength from the visible region of the spectrum.

This results in transitions from one 4f orbital to another 4f orbital known as f-f transition. The Lanthanides were first discovered in when a unusual black mineral was found in Ytterby, Sweden.

This mineral, now known as Gadolinite, was later separated into the various Lanthanide elements. In , Professor Gadolin obtained yttria, an impure form of yttrium oxide, from the mineral. The lanthanides occur naturally in many minerals but are most concentrated in monazite, a heavy dark sand, found in Brazil, India, Australia, South Africa, and the United States. The lanthanides have many scientific and industrial uses. Their compounds are used as catalysts in the production of petroleum and synthetic products.

Lanthanides are used in lamps, lasers, magnets, phosphors, motion picture projectors, and X-ray intensifying screens. Actinoids have low ionisation enthalpy than lanthanoids because 5 f electrons will have more effective shielding than 4 f electrons. The outer electrons are not tightly held and hence responsible for bonding.

Lanthanides are difficult to separate from each other because of similarities in their physical and chemical properties. Most separation processes take advantage of a small decrease in ionic radius that occurs across the lanthanide series. They can be mixed together but always separate back into different layers.

The reason why Lanthanides and Actinides are located at the bottom of the periodical table is because of their properties and in the block in which electrons fill up. The reason why inner-transition metals are located at the bottom of the periodic table, separated from the rest is because they all fill the f-block.

Are all lanthanides radioactive? Category: science chemistry. The lanthanide series can be found naturally on Earth. Only one element in the series is radioactive.