Physical Properties
How this element behaves in real-world conditions.
- State (25°C)
- Gas
- Density
- 0.0001785 g/cm³
- Melting Point
- -272.2 °C
- Boiling Point
- -268.93 °C
Atomic Structure
Core identity and periodic table positioning.
Electromagnetic Properties
How this element attracts and exchanges electrons.
- Electronegativity
- Not available
- Ionization Energy
- 24.587 eV
- Electron Affinity
- -0.52 eV
- Metallic Character
- Nonmetal
Hero / Identity Section
Core identity profile for Helium with periodic placement and electron context.
- Element Name
- Helium
- Symbol
- He
- Atomic Number
- 2
- Atomic Mass
- 4.0026
- Group
- 18
- Period
- 1
- Block
- S
- Category
- Noble Gas
- Standard State
- Gas
- Electron Configuration (Full)
- 1s2
- Electron Configuration (Noble Gas)
- 1s2
- Valence Electrons
- 2
Quick Facts Card (Table Layout)
Fast-reference values for physical and energetic properties.
Atomic Radius
31 pm
Ionic Radius
Not available in current dataset
Electronegativity (Pauling)
Not available in current dataset
1st Ionization Energy
24.587 eV
Electron Affinity
-0.52 eV
Density
0.000179 g/cm³
Melting Point
-272.2 °C
Boiling Point
-268.93 °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
He
Row 1, Column 18
Bohr Model Diagram
He
Educational shell model for electron arrangement.
Electron Shell Diagram
- K shell2
Orbital Configuration Diagram
1s2/2
Phase Illustration
Gas
Dispersed gas
Atomic Structure Section
Nuclear composition and electron shielding interpretation.
- Protons
- 2
- Neutrons (Most Abundant Isotope Estimate)
- 2
- Electrons
- 2
- Electron Configuration Breakdown
- 2
- Shielding Explanation
- Core electrons (~0) 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
- 0 (dominant; limited compounds for heavier members)
- Reactivity Summary
- Generally very low chemical reactivity due to filled valence shells.
- Acid/Base Behavior
- Largely inert under ordinary acid/base conditions.
- Bonding Behavior
- Monatomic gases with limited bonding except under extreme conditions.
- Typical Compounds
- Few specialized compounds (mostly heavier noble gases)
- Periodic Trend Comparison (Group Neighbors)
- Compared with Ne, this element is higher in the group and often shows a smaller radius with stronger effective attraction to valence electrons.
Isotopes & Nuclear Data
Isotope stability and abundance notes for learning-oriented nuclear context.
- Stable Isotopes
- Stable isotopes are known. Most abundant isotope is commonly represented near He-4.
- Radioactive Isotopes
- Radioactive isotopes exist alongside stable isotopes.
- Natural Abundance (%)
- Naturally occurring with isotope-dependent abundance.
- Half-life (If Applicable)
- Stable isotopes have no half-life; radioactive isotopes have isotope-specific half-lives.
- Nuclear Spin (Optional Advanced)
- Advanced isotope-level data is not included in the current core dataset.
- Most Abundant Isotope (Estimate)
- He-4
Applications & Uses
How this element appears in industry, biology, medicine, and technology.
- Industrial Uses
- Used in lighting, shielding atmospheres, cryogenics, and leak detection.
- Biological Role
- No essential nutrient role for most members under normal physiology.
- Medical Use
- Some used in respiratory mixtures, imaging, or anesthesia support contexts.
- Technological Relevance
- Important for plasma systems, lasers, and inert atmospheres.
- Environmental Impact
- Generally low reactivity in the environment; impacts mainly from extraction/energy use.
Safety & Handling
General hazard guidance for educational reference and lab awareness.
- Toxicity
- Chemically low toxicity, but asphyxiation risk exists in oxygen-deficient spaces.
- Flammability
- Nonflammable.
- Storage Considerations
- Store in compressed-gas cylinders with pressure and ventilation controls.
- Regulatory Classification
- Typically classified as inert compressed gases.