Element identity
Atomic number, periodic identity and reference mass/isotope conventions are established and source-reviewed.
Atomic / electronic model
Atomic configurations and orbital teaching models are reference interpretations; heavy-element electronic structure is more complex than a classical shell picture.
Nuclear / isotope data
Half-lives, isotope identities and decay information are taken from evaluated nuclear-data/reference sources and remain isotope-specific.
Material / phase data
Ordinary bulk and phase values are shown only where defensible; solid-state transitions are kept separate from melting.
Geography / safety boundary
Occurrence, discovery and public research context may be mapped. Operational radioactive-material inventories, access routes and sensitive facility details are intentionally not mapped.
The lens describes evidence status, not confidence theatre. “Unknown” is kept unknown, and teaching schematics are not presented as direct measurements.
Plutonium (Pu)
Plutonium is a radioactive actinide with complex 5f-electron chemistry, several solid allotropes and isotope-dependent nuclear behavior. It is best understood by separating atomic chemistry, materials science and nuclear properties rather than treating “plutonium” as one simple fact.
Plutonium atomic number, mass, electron configuration and key properties
Plutonium: quick answers
How many protons, neutrons and electrons does plutonium have?
Plutonium’s atomic number is 94, so every plutonium atom has 94 protons, and a neutral atom also has 94 electrons. Plutonium has no stable isotopes, so the number of neutrons depends on which isotope you mean.
What is the symbol for plutonium?
The chemical symbol for plutonium is Pu.
Is plutonium a solid, liquid or gas at room temperature?
Plutonium is a solid at room temperature (about 25 °C).
What family (group) is plutonium in?
Plutonium is an actinide, in period 7 (the f-block row shown below the main table) of the periodic table.
What is the electron configuration of plutonium?
The ground-state electron configuration of plutonium is [Rn] 5f⁶ 7s².
From atomic number to chemistry
Read these as a chain of causes, not as isolated facts. Each step links to the concept hub if you want the underlying idea explained.
94 protons define plutonium; a neutral atom contains 94 electrons.
This reviewed ground-state reference connects atomic structure to the element’s chemistry.
Periodic position supplies family context, but element-specific evidence and exceptions still matter.
Isotope notation separates proton identity from neutron count and nuclear behavior.
Plutonium in its period and family
Plutonium lies among the actinides between neptunium and americium. Closely spaced 5f, 6d and 7s energies, relativistic effects and changing 5f participation make actinide trends more complex than simple main-group patterns.
Plutonium Visual Lab
Decode the plutonium tile, rotate a ²³⁹Pu teaching nucleus, inspect qualitative 5f/7s orbital shapes, explore the unusually rich allotrope sequence and connect plutonium to controlled nuclear science, space power and environmental stewardship.
Every mark points to one exact feature
The numbered markers explain the same information system used throughout Element Lookup. Unknown or predicted fields remain visibly labelled rather than being replaced with guesses.
Plutonium in one minute
Atomic number 94 means 94 protons.
The reference ground-state configuration is [Rn] 5f⁶ 7s².
Plutonium has no stable isotopes.
Elemental plutonium has an unusually complex sequence of solid allotropes before melting.
Plutonium handling belongs to highly regulated professional environments; this page stays conceptual and non-operational.
Shell rings organize electron counts. They are not electron trajectories or orbital shapes.
2 · 8 · 18 · 32 · 24 · 8 · 2 electrons
Selected 7s and representative 5f (m=0, z(5z²−3r²)-type angular form) teaching views. Plutonium is an actinide with strongly coupled 5f/6d/7s physics; a simple one-electron orbital sketch cannot reproduce the many-electron solid.
Room-temperature α-Pu: monoclinic P2₁/m, 16 atoms per unit cell, eight crystallographically distinct sites. The viewer is evidence-aware: measured structures are identified as such; unknown bulk structures stay unknown.
Teaching visualization; not a literal finite sample or thermal trajectory.What this model does—and does not—show
Selected 7s and representative 5f (m=0, z(5z²−3r²)-type angular form) teaching views. Plutonium is an actinide with strongly coupled 5f/6d/7s physics; a simple one-electron orbital sketch cannot reproduce the many-electron solid.
Where do I meet plutonium?
Clickable learning cards connect the element to materials, environment, technology, biology or research - depending on what the evidence actually supports.
Research reactors + fuel cycles
Plutonium isotopes occur in reactor fuel-cycle science; this page gives only high-level context.
One element, unusually many solid structures
Plutonium is a reminder that “solid” is not one structure: several allotropes occur across temperature ranges.
Low-temperature solid
Alpha plutonium is the ordinary low-temperature allotrope and has a complex low-symmetry structure.
Uranium, plutonium and americium
Across the actinides, 5f electrons become progressively more involved in localized and bonding behavior, while nuclear properties change isotope by isotope.
| Configuration | [Rn] 5f³ 6d 7s² |
|---|---|
| Context | early actinide |
| Configuration | [Rn] 5f⁶ 7s² |
|---|---|
| Context | six common solid allotropes |
| Configuration | [Rn] 5f⁷ 7s² |
|---|---|
| Context | later actinide |
Plutonium properties: atomic, physical, thermal and chemical
Categories follow the science of this element rather than a fixed decorative template. Each row carries condition/provenance context and an evidence label; unknown values stay unknown.
| Property | Value | Context / provenance | Evidence |
|---|---|---|---|
| Atomic number | 94 | Source-reviewed; see Sources below | Evaluated |
| Relative atomic mass | [244] | Source-reviewed; see Sources below | Evaluated |
| Ground-state electron configuration | [Rn] 5f⁶ 7s² | Source-reviewed; see Sources below | Evaluated |
| Group / period / block | Group Actinide · Period 7 · f-block | Periodic-table placement | Evaluated |
| Electronegativity | ≈1.3 | Source-reviewed; see Sources below | Evaluated |
| Reference isotope | ²³⁹Pu | Source-reviewed; see Sources below | Evaluated |
| Property | Value | Context / provenance | Evidence |
|---|---|---|---|
| State context | Solid | Source-reviewed; see Sources below | Evaluated |
| Density | ≈19.7 g/cm³ (α-Pu context) | Source-reviewed; see Sources below | Predicted |
| Material / molecular structure | α-Pu monoclinic (P2₁/m) | Room-temperature α-Pu: monoclinic P2₁/m, 16 atoms per unit cell, eight crystallographically distinct sites | Measured |
| Classification | Actinide · radioactive synthetic/trace natural element | Periodic-table / chemistry classification | Evaluated |
| Structure-model scope | Room-temperature α-Pu: monoclinic P2₁/m, 16 atoms per unit cell, eight crystallographically distinct sites | Teaching visualization; exact crystallographic coordinates are not implied unless stated. | Reviewed |
| Property | Value | Context / provenance | Evidence |
|---|---|---|---|
| Melting / transition reference | 913 K | Source-reviewed; see Sources below | Evaluated |
| Boiling / gas reference | 3501 K | Source-reviewed; see Sources below | Evaluated |
| Phase-path context | At approximately ambient pressure, plutonium passes through several solid allotropes before melting near 913 K. The multiple solid transitions are first-class regions, not one generic “solid” block. | Shared phase registry drives the slider, regions and markers. | Evaluated |
| Condition warning | Temperature and pressure define phase behavior; purity/allotropy may matter. | Teaching condition statement | Reviewed |
| Property | Value | Context / provenance | Evidence |
|---|---|---|---|
| Common oxidation states | +3, +4, +5, +6 important | Source-reviewed; see Sources below | Evaluated |
| Ion / common ion context | Pu⁴⁺ (common chemistry) | Source-reviewed; see Sources below | Evaluated |
| Periodic chemistry context | Plutonium lies among the actinides between neptunium and americium. Closely spaced 5f, 6d and 7s energies, relativistic effects and changing 5f participation make actinide trends more complex than simple main-group patterns. | Element-specific interpretation | Reviewed |
| Chemistry caution | Elemental form, ions and compounds are distinct chemical objects. | Interpretive teaching rule | Reviewed |
| Property | Value | Context / provenance | Evidence |
|---|---|---|---|
| ²³⁸Pu | ≈87.7 y | strong decay-heat source used in some space-power systems | Evaluated |
| ²³⁹Pu | ≈24,100 y | important reactor/fuel-cycle isotope | Evaluated |
| ²⁴⁰Pu | ≈6,560 y | common co-produced isotope | Evaluated |
| ²⁴⁴Pu | ≈80 million y | very long-lived isotope; trace primordial/natural occurrence has been studied | Evaluated |
| Teaching nucleus | ²³⁹Pu · 94 protons + 145 neutrons | Reference isotope used in the nucleus model | Reviewed |
| Property | Value | Context / provenance | Evidence |
|---|---|---|---|
| Page evidence note | Isotope and atomic data are evaluated; allotrope transition temperatures vary somewhat by purity/pressure/source and are shown as approximate teaching boundaries. No operational nuclear-material instructions are provided. | Evidence summary for this guide | Reviewed |
| Structure evidence | Room-temperature α-Pu: monoclinic P2₁/m, 16 atoms per unit cell, eight crystallographically distinct sites | Measured structure, labelled schematic, prediction or explicit unknown as applicable. | Reviewed |
| Map evidence rule | Real pins are reviewed examples; conceptual layers are used when pins would mislead. | Geography Explorer 2.0 | Reviewed |
| Source set | 5 primary/reference links listed below | Open the Sources section for the actual references. | Reviewed |
Is Plutonium a solid, liquid or gas? State at temperature
At approximately ambient pressure, plutonium passes through several solid allotropes before melting near 913 K. The multiple solid transitions are first-class regions, not one generic “solid” block.
Where on Earth is Plutonium found or produced?
Who discovered Plutonium, and when?
Element 94 was first produced and identified in research at Berkeley.
Its chemistry and nuclear properties were investigated rapidly during the early nuclear era.
Plutonium became central to reactor science, safeguards, environmental monitoring and actinide materials research.
Pu-238 radioisotope power systems enabled long-duration spacecraft missions far from the Sun.
Plutonium production and handling: conceptual only
Plutonium isotopes can be produced in nuclear reactors through neutron-capture and decay chains involving uranium isotopes.
Chemical separation and fabrication, where performed, occur only in specialized licensed facilities.
Different isotopes are selected or managed according to nuclear properties, decay heat and application.
Safeguards, radiological protection, criticality safety and waste management are integral professional disciplines.
What is plutonium used for?
Space power
Pu-238 is used as a heat source in selected radioisotope power systems.
Nuclear research
Plutonium isotopes are studied in reactor physics, actinide chemistry and materials science.
Standards + analysis
Specialized isotopic standards support safeguards, forensics and measurement science.
Historical weapons context
Plutonium has military history; Element Lookup intentionally provides no design, fabrication or optimization instructions.
Plutonium isotopes and natural abundance
²³⁸Pu
≈87.7 ystrong decay-heat source used in some space-power systems
²³⁹Pu
≈24,100 yimportant reactor/fuel-cycle isotope
²⁴⁰Pu
≈6,560 ycommon co-produced isotope
²⁴⁴Pu
≈80 million yvery long-lived isotope; trace primordial/natural occurrence has been studied
Five-question Plutonium check
Does plutonium have any stable isotopes?
What is the room-temperature alpha-plutonium structure?
Why does the plutonium temperature bar show several solid regions?
Which plutonium isotope is used as a heat source in some space-power systems?
Why is the plutonium page intentionally non-operational?
Plutonium questions students commonly ask
Each answer starts with the direct fact, then explains the chemistry, evidence or material context so the result is understandable rather than merely memorized.
Does plutonium occur naturally?
Short answer: Tiny trace amounts can occur through rare nuclear processes, but most plutonium encountered by humans is produced in reactors.
Research reactors + fuel cycles Plutonium isotopes occur in reactor fuel-cycle science; this page gives only high-level context. Environment Environmental monitoring can track trace plutonium from historical releases and nuclear activities.
Key point: Use the direct answer together with the material, isotope and evidence context shown elsewhere on the page.
Why does plutonium have so many solid phases?
Short answer: Its 5f electrons sit near the boundary between localized and bonding behavior, producing unusually delicate phase energetics.
Elemental plutonium has an unusually complex sequence of solid allotropes before melting. At approximately ambient pressure, plutonium passes through several solid allotropes before melting near 913 K. The multiple solid transitions are first-class regions, not one generic “solid” block.
Key point: The mechanism matters: connect the observed behavior to electron structure, bonding, phase or the specific material form rather than memorizing the result alone.
Is every plutonium isotope equally dangerous?
Short answer: No. Isotopes differ in half-life, decay mode and specific activity, while chemical toxicity and exposure pathway also matter.
²³⁸Pu: ≈87.7 y: strong decay-heat source used in some space-power systems. ²³⁹Pu: ≈24,100 y: important reactor/fuel-cycle isotope.
Key point: Radioactivity is isotope-specific; do not apply one isotope’s nuclear behavior to every atom of the element.
Why is this page intentionally non-operational?
Short answer: Plutonium is radioactive and strategically sensitive. The educational goal is scientific understanding, not instructions for handling or processing nuclear material.
Plutonium handling belongs to highly regulated professional environments; this page stays conceptual and non-operational. Research reactors + fuel cycles Plutonium isotopes occur in reactor fuel-cycle science; this page gives only high-level context.
Key point: The mechanism matters: connect the observed behavior to electron structure, bonding, phase or the specific material form rather than memorizing the result alone.
Scientific sources for Plutonium
- Royal Society of Chemistry — Plutonium
- NIST — Plutonium elemental/atomic data
- Los Alamos National Laboratory — Plutonium periodic-table entry
- IAEA Nuclear Data Services
- Los Alamos / published plutonium metallurgy — α-Pu structure and allotropes
Questions to ask next about Plutonium
A good element lesson should lead to the next useful question, not end after a list of facts.
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