Atomic Number 61
Promethium (Pm)
GroupLanthanide
Period6
BlockF
State @ 25°CSolid
Valence Electrons2–3 (f-block, variable)
Electron Config (Noble)[Xe] 6s2 4f5
61PmPromethium145
Tap related elements to compare trends across group and period.
Physical Properties
How this element behaves in real-world conditions.
- State (25°C)
- Solid
- Density
- 7.26 g/cm³
- Melting Point
- 1042 °C
- Boiling Point
- 3000 °C
Atomic Structure
Core identity and periodic table positioning.
- Atomic Number
- 61
- Atomic Weight
- 145
- Atomic Radius
- 236 pm
- Block
- F
- Group
- Lanthanide
- Period
- 6
Electromagnetic Properties
How this element attracts and exchanges electrons.
- Electronegativity
- 1.13
- Ionization Energy
- 5.55 eV
- Electron Affinity
- 0.5 eV
- Metallic Character
- Metal
Hero / Identity Section
Core identity profile for Promethium with periodic placement and electron context.
- Element Name
- Promethium
- Symbol
- Pm
- Atomic Number
- 61
- Atomic Mass
- 145
- Group
- Lanthanide Series
- Period
- 6
- Block
- F
- Category
- Lanthanide
- Standard State
- Solid
- Electron Configuration (Full)
- 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f5
- Electron Configuration (Noble Gas)
- [Xe] 6s2 4f5
- Valence Electrons
- 2–3 (f-block, variable)
Quick Facts Card (Table Layout)
Fast-reference values for physical and energetic properties.
Atomic Radius
236 pm
Ionic Radius
Not available in current dataset
Electronegativity (Pauling)
1.13
1st Ionization Energy
5.55 eV
Electron Affinity
0.5 eV
Density
7.26 g/cm³
Melting Point
1,042 °C
Boiling Point
3,000 °C
Heat Capacity
Not available in current dataset
Thermal Conductivity
Not available in current dataset
Visual Components
Visual learning views for table position, shells, orbitals, and phase behavior.
Highlighted Position in Periodic Table Grid
Pm
Row 9, Column 8
Bohr Model Diagram
Pm
Educational shell model for electron arrangement.
Electron Shell Diagram
- K shell2
- L shell8
- M shell18
- N shell23
- O shell8
- P shell2
Orbital Configuration Diagram
1s2/2
2s2/2
2p6/6
3s2/2
3p6/6
4s2/2
3d10/10
4p6/6
5s2/2
4d10/10
5p6/6
6s2/2
4f5/14
Phase Illustration
Solid
Solid lattice
Atomic Structure Section
Nuclear composition and electron shielding interpretation.
- Protons
- 61
- Neutrons (Most Abundant Isotope Estimate)
- 84
- Electrons
- 61
- Electron Configuration Breakdown
- 2 • 8 • 18 • 23 • 8 • 2
- Shielding Explanation
- Core electrons (~59) shield part of the nucleus, reducing attraction felt by outer electrons compared with the full nuclear charge.
- Effective Nuclear Charge (Estimate)
- 2
Chemical Properties Section
Category-guided chemistry behavior with periodic context for comparison.
- Common Oxidation States
- +3 (most common), some +2/+4
- Reactivity Summary
- Reactive metals that tarnish in air and react with water/acids to varying degrees.
- Acid/Base Behavior
- Forms basic oxides and hydroxides; mainly ionic chemistry.
- Bonding Behavior
- Predominantly ionic in salts with coordination behavior in complexes.
- Typical Compounds
- Oxides, Fluorides, Phosphors and coordination compounds
- Periodic Trend Comparison (Group Neighbors)
- Compared with Lu, this element is lower in the group and typically has a larger atomic size and lower ionization tendency.
Isotopes & Nuclear Data
Isotope stability and abundance notes for learning-oriented nuclear context.
- Stable Isotopes
- No fully stable isotopes are known for this element.
- Radioactive Isotopes
- All known isotopes are radioactive.
- Natural Abundance (%)
- Usually trace-level or synthetic; natural abundance is limited.
- Half-life (If Applicable)
- Half-life varies by isotope and should be checked from isotope-specific references.
- Nuclear Spin (Optional Advanced)
- Advanced isotope-level data is not included in the current core dataset.
- Most Abundant Isotope (Estimate)
- Pm-145
Applications & Uses
How this element appears in industry, biology, medicine, and technology.
- Industrial Uses
- Used in magnets, phosphors, polishing compounds, and catalysts.
- Biological Role
- No broad essential biological role for most lanthanides.
- Medical Use
- Selected compounds used in imaging contrast and targeted technologies.
- Technological Relevance
- Crucial for high-performance magnets, optics, and energy systems.
- Environmental Impact
- Mining and refining can create localized ecological burdens.
Safety & Handling
General hazard guidance for educational reference and lab awareness.
- Toxicity
- Generally moderate toxicity with dust/inhalation controls recommended.
- Flammability
- Finely divided powders can ignite; bulk metals are less flammable.
- Storage Considerations
- Keep dry, limit oxidation, and avoid dust and incompatible oxidants.
- Regulatory Classification
- Regulated by metal dust exposure, handling, and waste controls.