Page 124 - The Periodic Table Book

92
U Uranium

Discovery: 1789
92 92 146 State: Solid
Actinides Named after the planet Uranus, uranium was contain uranium dioxide, which
These black sections
the first known radioactive element. In the early
20th century, some manufacturers used uranium
in glass bowl glazes, only to realize later is the main source of uranium.
that it was a harmful metal. Chunk of pure uranium
An unstable form, called
uranium-235, is used as
fuel in nuclear
reactors and Uraninite
in atomic
bombs.

This sample of pure
uranium is waste
from a nuclear plant.
Uranium mixed into
glass makes this bowl
glow bright green under
ultraviolet (UV) lamps.

Glass bowl

93
Np Neptunium

State: Solid
93 93 144 Discovery: 1940
The radioactive
elements in this
mineral decay to
form neptunium.
This cyclotron,
built in 1938, was
used to discover
neptunium.

Uraninite of California, Berkeley, USA
Cyclotron at the University

Sitting next to uranium in the periodic
table, neptunium was named after the
planet Neptune. It exists in small amounts
in radioactive ores, such as aeschynite.
It forms during nuclear explosions and
was first identified inside a machine called
a cyclotron. There are no known uses
122 for neptunium.

122-123_Uranium_Neptunium_Plutonium_Americium.indd 122 12/12/16 5:39 pm