Lawrencium (Lr)
Actinide · Radioactive · Synthetic
Lawrencium closes the actinide series. Named for Ernest Lawrence, inventor of the cyclotron, it is made a few atoms at a time, and even its electron configuration proved surprising enough to spark debate about the table's layout.
Position on the periodic table
Atomic properties
| Atomic number | 103 |
|---|---|
| Atomic mass | 266 amu |
| Electron configuration | 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d10 6p6 7s2 5f14 7p1 |
| Noble gas shorthand | [Rn] 5f14 7s2 7p1 |
| Electrons per shell | 2, 8, 18, 32, 32, 8, 3 |
| Valence electrons (outer shell) | 3 |
| Common oxidation states | +3 |
| Electronegativity (Pauling) | 1.3 |
| Covalent radius (approx.) | Not available |
| First ionization energy | 470 kJ/mol |
| Electron affinity | -30 kJ/mol |
Physical properties
| State at 25 °C | Solid |
|---|---|
| Density | Not available |
| Melting point | 1626.8 °C (1900 K) |
| Boiling point | Not available |
| Appearance | Not available |
| Radioactive | Yes |
| Origin | Synthetic (lab-made) |
Electron configuration of lawrencium
Lawrencium's ground-state electron configuration is 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d10 6p6 7s2 5f14 7p1, usually shortened to [Rn] 5f14 7s2 7p1. Its electrons occupy 7 shells (2, 8, 18, 32, 32, 8, 3), placing it in period 7 of the d-block. Explore it interactively in the electron configuration calculator.
Uses of lawrencium
- Fundamental research only
Biological role: None.
Occurrence: Entirely synthetic.
History and discovery
Discovered: 1961 — Lawrence Berkeley National Laboratory. Name origin: Named after Ernest O. Lawrence.
Ghiorso's team at Berkeley reported element 103 in 1961; Dubna contributed key confirmations.
Safety notes
Radioactive; research only.
Educational context only — always follow your school's laboratory rules and never handle chemicals without proper supervision. See our disclaimer.
Practice questions
Quick practice: Lawrencium
1. What is the chemical symbol of Lawrencium?
2. What is the atomic number of Lawrencium?
3. Which category does Lawrencium belong to?
4. What is the state of Lawrencium at room temperature?
5. Which period of the periodic table is Lawrencium in?
Lawrencium FAQs
What is the atomic number of lawrencium?
Lawrencium's atomic number is 103 — every lawrencium atom has 103 protons in its nucleus.
What is the symbol for lawrencium?
Lr. Named after Ernest O. Lawrence.
Is lawrencium a metal, nonmetal, or metalloid?
Lawrencium is classified as a actinide.
What state is lawrencium at room temperature?
At about 25 °C, lawrencium is a solid. It melts at 1626.8 °C.
What is lawrencium used for?
Key uses include: fundamental research only.
Related elements
Keep working with this element
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