By: Madeline Whiting


Thallium is a chemical element that can be found in the periodic table. It has eighty one protons and an atomic number of two hundred and four. This element is a metal, but can be cut with an ordinary butter knife! Also, because thallium was odorless and tasteless, it was once used for bug and rat poising! This item was banned in the United states though.


Thallium was discovered by a British scientist by the name of William Crookes in 1861. He named this element after a Greek word 'thallos'. This means a green twig. This was because the element had a green vertical line running through it. Crookes discovered the element by using a spectroscopic. This means that he analyzed the light that was produced when the element was heated.


Thallium is part of the Boron group in the periodic table. The Boron group are poor metals. This means that even though these metals can conduct energy and are malleable, these element can not do these things very well. The Boron group also reacts well with other element near by. This is because the Boron group has three valence electrons. Every element wants a full shell, so thallium is reactive because it wants eight valence electrons.

Interesting Facts

Some interesting facts about thallium is that: Thallium is the most toxic element on the periodic table in its natural form. Another fun fact about this element is that there was a murder in the 1960's called the teacup Poisoner. A man killed three other people by putting thallium in their tea! Finally, the element was once used as a perfume! This toxic substance was taken off shelves once people saw the consequences.