Atomic Number: 81

Protons: 81

Electrons: 81

Neutrons: 123

Average Atomic Mass: 204.383 amu

Isotopes: Tl-200, Tl-201, Tl-202, Tl-203, Tl-204, Tl-205

Discovery: Thallium was founded by Sir. William Crookes in 1861 in England.

Name: Thallium was named from the Greek word "thallos" meaning green twig or green shoot because it produced a green line with spectroscopic analysis.

Uses: Thallium is used to kill ants and rodents. It is also used in photocells (solar panels), and infrared detectors.