A Visual Encyclopedia of the Periodic Table

121

Actinides

121

The name protactinium means “before

actinium”. This is because a uranium atom

decays to form a protactinium atom, which

then quickly breaks down into an actinium atom.

Small quantities of protactinium are found in

ancient sands and mud. Geologists use Geiger

counters to carry out research to calculate

how old the sands are.

This vibrant green

radioactive mineral contains

tiny amounts of protactinium.

These used nuclear fuel

rods contain protactinium.

Protactinium

research

Nuclear waste

Protactinium

This bottle

contains a

protactinium

sample.

State: Solid

Discovery: 1913

91 91 140

Torbernite

This brittle,

shiny ore

feels waxy.

Pa

91

A Geiger counter measures

the sample’s radioactivity.

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