ElementsWhat is lawrencium?
Lawrencium is a radioactive element and the last of the actinides. It is made a few atoms at a time.
What is lawrencium used for?
Research only.
Where the name comes from
In honour of Ernest Lawrence, inventor of the cyclotron.
Key facts
- Symbol
- Lr
- Atomic number
- 103
- Atomic mass
- 266.120 u
- Family
- Actinide
- Period
- 7
- Group
- none (f-block)
- Block
- f
- State at room temperature
- Solid
- Melting point
- 1,627 °C (1,900 K, 2,960 °F)
- Boiling point
- not measured
- Density
- not measured
- Electrons per shell
- 2, 8, 18, 32, 32, 9, 2
- Electron configuration
- [Rn]7s2 5f14 6d1
- Common oxidation states
- +3
- Electronegativity (Pauling)
- 1.3
- First ionisation energy
- not measured
- Electron affinity
- no value
- Atomic radius (van der Waals)
- no value
- Discovered
- 1961
Place in the periodic table
Lawrencium is element number 103. It sits in period 7 (row 7) of the periodic table, in the separate row of actinides drawn below the main table, and belongs to the f-block. Just before it comes nobelium (102), and just after it comes rutherfordium (104).
Family: Actinides.
Physical properties
At room temperature lawrencium is a solid. Its melting point is about 1,627 °C. Its boiling point has not been measured reliably.
Inside the atom
An atom of lawrencium has 103 protons in its nucleus and, when neutral, 103 electrons around it. The electrons are arranged in 7 shells: 2, 8, 18, 32, 32, 9, 2. The outermost shell holds 2 electrons. Written in full, the electron configuration is [Rn]7s2 5f14 6d1.
Its electronegativity on the Pauling scale is 1.3. This number shows how strongly an atom pulls shared electrons towards itself: fluorine, the strongest, is 3.98. One mole of lawrencium weighs 266.120 grams, so a single gram contains about 2.26 × 1021 atoms.
The ring picture is a simple model that only counts the electrons in each shell. Real atoms do not look like this.
Next steps
- Work out the weight of a compound that contains lawrencium with the molar mass calculator.
- Compare it with every other element in the sortable list.
- Test yourself with the symbol quiz.
Figures on this page are from PubChem (U.S. National Library of Medicine), as downloaded on 11 November 2026. See About and data sources.