Chemical element · Atomic number 103

Lawrencium

Lawrencium in the periodic table: atomic number 103, electron configuration, atomic mass, physical data, oxidation states, media credit and visible sources.

Lr

Actinide

solid

[266.120] u

Generated illustration of Lawrencium (Lr): an ampoule with the symbol and atomic number, not a photoGenerated illustration

Generated illustration, Quanta Study. Not a photograph of a sample.

Generated illustration of Lawrencium; the image does not show a sample of the element.

Transuranic element handled only in specialised laboratories in tiny amounts; no freely licensed sample photograph is available.

Code-native illustration with the Quanta Study mark inside the image; not a photograph, no AI model involved.

Licence and image notes from Quanta Study

Atomic classification

Lawrencium in the Bohr shell modelThis shows the electron distribution of the neutral atom in a simplified shell model.: 2 · 8 · 18 · 32 · 32 · 9 · 2

Shell occupancy

Lawrencium in the Bohr shell model

This shows the electron distribution of the neutral atom in a simplified shell model.

K · n=1
2 electrons
L · n=2
8 electrons
M · n=3
18 electrons
N · n=4
32 electrons
O · n=5
32 electrons
P · n=6
9 electrons
Q · n=7
2 electrons
Shell occupancy is derived from the versioned PubChem electron configuration. Dot angles are schematic and do not represent orbitals.
Electron configuration
[Rn]7s2 5f14 6d1
Electrons per shell
2 · 8 · 18 · 32 · 32 · 9 · 2
Group
not reported
Period
7
Block
F
Element category
Actinide

Physical and chemical properties

Atomic mass
[266.120] u
Standard state
solid
Density
not reported
Melting point
1,900 K
Boiling point
not reported
Electronegativity
1.3 (Pauling)
First ionisation energy
not reported
Oxidation states
+3
Discovery
1961

Safety and periodic classification

Safety

Safe handling cannot be inferred from Lawrencium's position in the periodic table alone. Laboratory, classroom and disposal decisions must follow the documentation for the exact material and its safety data sheet.

Position and comparison

Lawrencium is in period 7 and the F block. Its direct neighbours by atomic number are Nobelium and Rutherfordium. The recorded Pauling electronegativity is 1.3. Periodic trends are compared only through the separately sourced neighbouring values.

Sources and scope

PubChem attributes element data to sources including IUPAC, NIST and IAEA. Quanta stores the referenced snapshot locally and leaves unknown values unavailable.

Where Lawrencium sits among the 118 elements

The table compares the reported values for Lawrencium with every other element that carries the same value in the snapshot. A rank is not a judgement, it is orientation: it says how unusual this value is across the periodic table.

ValueLawrenciumPosition in the data set
Melting point1,900 KRank 21 of 103 elements with a reported value. Highest: Carbon.
Electronegativity (Pauling)1.3Rank 71 of 95 elements with a reported value. Highest: Fluorine.

All values and ranks come from the PubChem Periodic Table snapshot, retrieved on 2026-07-15. Elements without a reported value are excluded, so the population differs per row.

The neighbours of Lawrencium in the periodic table

Place in the table
No group number, period 7, F block. Classified as actinide, solid at standard conditions.
Direct neighbours
Atomic number 103. Preceded by Nobelium, followed by Rutherfordium.
Discovery
Recorded in the snapshot as: 1961. Who, where and under what circumstances is not part of that record, so this page carries the sourced year and no discovery narrative.
Oxidation states
+3. They follow from the electron configuration [Rn]7s2 5f14 6d1 and indicate which compounds to expect.

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