Lawrencium is a radioactive element at the end of the actinide series. It has been produced through reactions involving californium and boron nuclei. The quantities involved are suited to specialized research, so its place in the table should be distinguished from observations of an ordinary bulk material.
FROM ELEMENT TO APPLICATION
AN ELEMENT IN CONTEXT
What did measuring lawrencium’s first ionization energy test?
Lawrencium atoms in ionization-energy measurements
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Define electron removal
The first ionization energy concerns removing the most weakly bound electron from a neutral atom. It is a precise atomic quantity, distinct from a chemical bond energy.
Explore the model (optional)
LrFORM → INTERACTION → CONSEQUENCE
Follow the explanation in either direction. These are authored steps, not a physical clock.
Optional: check your understanding
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Which claim stays closest to the measurement?
Atomic identity, reference properties and structure models
INTERACTIVE 3D103 visible sites
An electron censusDrag to rotate · scroll or pinch to zoom
[Rn] 5f14 7s2 7p1. Grouping electrons by principal shell connects the neutral-atom configuration to periodic-table patterns.
What this representation means
A three-dimensional counting diagram. Dots are count markers, not measured electron positions; spherical placement and spacing are arbitrary. There are no electron trajectories here. Orbitals describe quantum states.
Closing a series while challenging a simple pattern
Lawrencium’s discovery developed through Berkeley and Dubna experiments across the 1960s, with credit ultimately shared. Its name honors Ernest Lawrence, whose cyclotron made much heavy-element research possible. The established name was retained in the 1997 naming settlement. Later ionization measurements made lawrencium important for a different reason: the last actinide provides a sensitive test of whether simple periodic expectations survive the electronic effects of a very heavy .
1961
Early Berkeley report
Berkeley researchers report evidence for element 103.
1997
Name retained
The international naming settlement retains lawrencium and the symbol Lr.
Lawrencium is produced artificially in accelerator experiments and has no natural resource. Studies use radioactive atoms in quantities too small for ordinary material applications. The available and its behavior constrain experiments, while the designation element 103 identifies the count shared by all those nuclear variants.
The listed configuration follows RSC’s 7p1 assignment, which reflects relativistic electronic-structure calculations rather than the simple 6d1 analogy with lutetium. Measured ionization energy supports the theoretical picture but is not a direct image of every orbital. Lawrencium illustrates why a neutral-atom prediction and an experimentally measured observable should be distinguished.
Each section links its supporting references. Descriptions and diagrams were authored for this atlas. Source checks completed. Source checks dated 2026-09-06.
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Family labels and the group-3 layout are teaching conventions. A table position does not establish an unknown bulk property. Electronic configurations refer to neutral atoms; ions and material environments require their own account.
Read each reference property together with its units, conditions and the reference information below.
Not yet recorded: electron affinity, second ionization energy, ground-state term symbol, van der waals radius, thermal conductivity, specific heat capacity, electrical resistivity, crystal structure, lattice parameter a, space group, abundance in seawater, abundance in the universe, annual production, supply-risk listing, hazard classification, biological role, cas registry number, pubchem cid, wikidata item. These families are declared and awaiting an ingestion run against the source each names; they are listed here rather than shown as empty rows.
Physical
Intended reference: CRC Handbook of Chemistry and Physics · CRC Press
Phase at 20 °C
Not recorded
293.15 K, 101.325 kPa
Melting point
Not recorded
at standard pressure unless noted
Boiling point
Not recorded
101.325 kPa
Density
Not recorded
solids and liquids at 293 K; gases at 273 K and 101.325 kPa
Atomic and electronic
Intended reference: Pauling electronegativity scale · Widely tabulated; original in The Nature of the Chemical Bond
Electronegativity in Pauling
1.3 Pauling
Pauling scale
First ionization energy in kJ/mol
470 kJ/mol
gas-phase neutral atom, ground state
Covalent radius
Not recorded
single-bond covalent radius
Common oxidation states
+3
states met in ordinary compounds; not exhaustive
Occurrence and identity
Intended reference: CRC Handbook of Chemistry and Physics · CRC Press
Abundance in the crust
Not recorded
upper continental crust, mass fraction
Has stable isotopes
Noderived
Discovery year in CE
1961 CEderived
WHERE IT SITS AMONG ITS NEIGHBORS
Electronegativity across period 7
Lr 1.3 Pauling · Lawrencium
Electronegativity across period 7. Exact values.
Ra
0.9
Ac
1.1
Th
1.3
Pa
1.5
U
1.38
Np
1.36
Pu
1.28
Am
1.13
Cm
1.28
Bk
1.3
Cf
1.3
Es
1.3
Fm
1.3
Md
1.3
No
1.3
Lr
1.3
The trend uses the same reference-property values as the periodic table. Elements with no recorded value are left out of the line rather than drawn at zero.
