Tennessine

Tennessine is a special kind of element that scientists made in a laboratory. Its symbol is Ts, and it has the atomic number 117. This makes it one of the heaviest elements ever created. Tennessine was named after the U.S. state of Tennessee, where important research happened to discover it.

The discovery of tennessine was announced in Dubna, Russia, by scientists from Russia and America in April 2010. After many tests and checks, the worldwide science groups officially recognized tennessine as a new element in 2016.

Tennessine is very unusual because it might be part of something called the "island of stability." This means that even though it is very heavy, some of its atoms can last for short periods—tens or hundreds of milliseconds. Scientists think tennessine behaves like a metal and is part of the group of elements called halogens, but its properties might be different because of powerful forces inside its atoms.

Introduction

Tennessine is a special kind of element that scientists created in a laboratory. It has the symbol Ts and the number 117, which tells us its place among all the known elements. Tennessine was named after the U.S. state of Tennessee, where important research work to discover it was done.

History

See also: Timeline of chemical element discoveries

Pre-discovery

In December 2004, scientists from the Joint Institute for Nuclear Research in Dubna, Moscow Oblast, Russia, planned an experiment with the Oak Ridge National Laboratory in Oak Ridge, Tennessee, United States, to create element 117. They wanted to combine an element called berkelium with calcium to make this new element. However, Oak Ridge could not provide the needed berkelium at that time because they had stopped making it. So, they waited until they could get enough berkelium.

Discovery

In 2008, Oak Ridge started making berkelium again. Scientists from Oak Ridge, Vanderbilt University, and the Joint Institute for Nuclear Research worked together. In late 2008, they got enough berkelium to try the experiment. After preparing the materials, the experiment began in July 2009 in Russia. In early 2010, they announced they had created element 117. They made it by combining berkelium and calcium, which created two different versions of the element.

Confirmation

Later, scientists checked their work by making one of the decay products of element 117 directly. Its properties matched what they had seen when element 117 broke apart. In 2012, they repeated the experiment and got the same results. In 2014, scientists in Germany also made element 117 and confirmed the discovery.

Naming

At first, element 117 was called ununseptium. In 2016, the discovery team decided to name it tennessine, after the region of Tennessee, where important research happened. The symbol for tennessine is Ts. The official naming happened in 2017.

Predicted properties

Other than nuclear properties, no properties of tennessine or its compounds have been measured. This is because tennessine is very hard to make and it breaks down quickly. Because of this, we only have guesses about what tennessine might be like.

Nuclear stability and isotopes

The stability of atoms gets weaker as the number of protons increases. All atoms with more than 82 protons do not have stable forms. This is because the protons push each other apart, and the force that holds the atom together can't keep them close for long. Some scientists think that for atoms with 114 protons and 184 neutrons, the atom might stay together longer. This is called the "island of stability." Tennessine is one of the heaviest atoms made so far, and its known forms break down very quickly, in less than one second. However, this is longer than scientists thought before they made it.

It is thought that one form of tennessine, called ²⁹⁵Ts, might last about 18 milliseconds. Scientists are trying to make this form using special reactions. Other heavier forms might also be possible. Some calculations suggest that very heavy forms of tennessine might last much longer, even longer than the age of the universe, but this is still just a guess.

Atomic and physical

Tennessine is thought to be in group 17 of the periodic table, below fluorine, chlorine, bromine, iodine, and astatine. These elements all have seven electrons in their outer shell. Tennessine, being very heavy, might show some metal-like properties. This is because as you go down the group, the elements tend to become more metallic.

Because tennessine is so heavy, its electrons move very fast, close to the speed of light. This changes how the electrons behave and could make tennessine act differently from the other elements in its group. For example, it might not easily gain an electron like the lighter halogens do.

Chemical

The known forms of tennessine break down too quickly to study its chemistry directly. However, scientists have made guesses about its chemical properties. Tennessine might not behave like the other elements in its group. For example, it might not easily gain an electron to complete its outer shell.

Tennessine might form different kinds of bonds compared to the other halogens. It might form bonds using different parts of its electrons, which could change how it reacts with other elements. Scientists predict tennessine could form compounds in different states, like +1, +3, and +5, but the +7 state seems unlikely.

The simplest compound of tennessine, called TsH, might have a longer bond than expected because of how its electrons behave. This could make the bond weaker than bonds in similar compounds of lighter elements.