81
Tl
Thallium
Thallium
Thallium (Tl)
Post-transition Metals · Solid · Period 6 · Group 13
Element Properties
- Atomic Number
- 81
- Symbol
- Tl
- Atomic Mass
- 204.383
- Category
- Post-transition Metals
- Standard State
- Solid
- Period
- 6
- Group
- 13
- Electronegativity
- 1.62
- Atomic Radius
- 196
- Ionization Energy
- 6.11
- Electron Affinity
- 0.2
- Oxidation States
- +3, +1
- Melting Point
- 577 K (303.85 °C)
- Boiling Point
- 1746 K (1472.85 °C)
- Density
- 11.8
- Electron Configuration
- [Xe]6s2 4f14 5d10 6p1
- Year Discovered
- 1861
Electron shells
[Xe]6s2 4f14 5d10 6p1
Electrons are arranged in shells (principal energy levels) around the nucleus. The diagram is a schematic — orbitals in the same shell are not drawn separately.
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Frequently asked questions
What is the atomic number of Thallium?
The atomic number of Thallium is 81, which equals the number of protons in its nucleus.
What is the atomic mass of Thallium?
The atomic mass of Thallium is approximately 204.383 u (one twelfth of the mass of a carbon-12 atom).
What is the electron configuration of Thallium?
The electron configuration of Thallium is [Xe]6s2 4f14 5d10 6p1.
Where is Thallium in the periodic table?
Thallium is located in period 6, group 13.
When was Thallium discovered?
Thallium was discovered in 1861.
Related elements
Same group
5
B
Boron
10.81
13
Al
Aluminum
26.982
31
Ga
Gallium
69.723
49
In
Indium
114.818
113
Nh
Nihonium
286.182