A Visual Encyclopedia of the Periodic Table

187

The Halogen Group

Tennessine

Ts

117

Atoms of astatine are unstable,

and typically break down after

just a few hours, into atoms

of lighter elements, such as

bismuth. This radioactive

element itself forms in a similar

way when atoms of a heavier

element called francium break

apart. Tiny amounts of this rare

element are found in uranium

ores, such as uraninite. The

Italian physicist Emilio Segrè was

one of the first scientists to isolate

a sample of pure astatine. He was

able to do so by using a particle

accelerator: this is a machine that

smashes together atoms and then

studies the results.

Tennessine is the youngest element in the

periodic table. It was produced in 2011, in the

Russian city of Dubna. The element was named

after the US state of Tennessee, home to the Oak

Ridge National Laboratory, which houses one

of the first, large-scale nuclear reactors ever built.

Only a few atoms of this halogen element have

ever been made. Even so, scientists have predicted

it to be a semi-metal, not a non-metal like all the

other halogens.

85 85 125

State: Solid

Discovery: 1940

State: Solid

Discovery: 2011 (predicted)

117 117 177

Nuclear Reactor, Oak Ridge National

Laboratory, Tennessee, USA

Atoms

of tennessine

existed for a

few seconds

after they were

formed.

U

ra

ni

ni

te

Astatine

At

85

Inside this mineral, unstable atoms

of the element francium are breaking

apart, forming astatine atoms.

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