# Protactinium

## Gimnazija, Jesenice, Slovenia

Protactinium: Protactinium is a rare earth metal; it naturally occurs in Zaire. It is one of the most expensive metals on Earth. But our inspiration, which lead to “chalk drawing”, was its radioactivity. When discussing the radioactivity, we always think of the damage from a nuclear bomb, so that is the point in the drawing. We must not forget that this precious element is also highly toxic therefore requires special handling, similar to plutonium. When we studied the data, we noticed quite a few scientists have studied this element. The identification was made in 1913, but the final name was established in 1949.The drawing was made by Jan Novak, with the help of classmates and their chemistry professor Natalija Bohinc.

Teacher: Natalija Bohinc,Gimnazija, Jesenice, Slovenia

### Atomic properties*

Name:

Symbol:

Atomic number:

Atomic mass:

Melting point:

Boiling point:

Density:

Electronegativity:

Number of isotopes:

State:

Colour:

Classification:

Protactinium

Pa

91

231.04 amu

1572°C

No data

15.4 g/cm3

1.5

1

Solid

Silvery-metallic**

Metallic**

* Haynes, W. M. (2011). CRC Handbook of Chemistry and Physics, 91st edition: http://www.hbcponline.com/ Retrieved April 7, 2011

** Winter, M. (2010). Home of the Periodic Table. Retrieved April 8, 2011, from Web Elements: http://www.webelements.com/