Thallium (Tl)
Thallium is a soft, toxic metal once used as rat poison. Its name means "green twig" for its bright green spectral line.
Properties of Thallium
- Atomic number
- 81
- Category
- Post-Transition Metal
- Atomic mass
- 204.38 u
- Electron configuration
- [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p¹
- Melting point
- 577 K (303.85 °C)
- Boiling point
- 1746 K (1472.85 °C)
- Density
- 11.85 g/cm³
- Electronegativity (Pauling)
- 1.62
- Appearance
- Silvery-white metal
- Discovered by
- William Crookes (1861)
Facts about Thallium
- Thallium is named after the Greek word for "green twig" because of its green spectral line!
- Thallium was once called "the poisoner's poison" because it's colorless and tasteless!
- Thallium is used in special glass that bends light for night-vision equipment!
- Thallium was discovered with a spectroscope — the same tool used to study starlight!