Periodic Table Quick Lookup

An interactive, offline reference tool for students, researchers, and lab technicians. Instantly access atomic data, compute molar masses, and perform common chemistry lookups. All calculations run locally in your browser—no data sent online.

Educational only. Follow your lab SOPs and SDS.

Using the Periodic Table Lookup Tool

This tool provides instant access to critical atomic and molecular data directly in your browser. It’s designed for quick verification during problem‑solving, lab calculations, or while studying.

Step‑by‑Step Usage

Locate an element by typing its symbol, name, or atomic number in the input field, or click directly on the table above.
View atomic properties instantly: atomic mass, group, period, electron configuration, electronegativity, and common oxidation states.
Optional: Enter a compound formula to calculate its molar mass and elemental composition.
Use the Quick Actions to highlight specific data (e.g., electron configuration).
Adjust decimal precision with the +/− buttons, then copy the results for your notes.

Realistic Examples

Iron (Fe): Atomic mass 55.845 u, electron configuration [Ar] 4s² 3d⁶, density 7.874 g/cm³ at 20°C.
Sodium (Na): Group 1, Period 3, atomic radius 186 pm, first ionization energy 496 kJ/mol.
Sulfuric acid (H₂SO₄): Molar mass ≈ 98.079 g/mol, composition H:2.06%, S:32.69%, O:65.25%.
Water (H₂O): Molar mass 18.015 g/mol, density ~0.998 g/mL at 20°C.

Reference Data & Typical Ranges

Property	Typical Range	Notes
Atomic Mass	1.008 – [294] u	Weighted average of isotopes; IUPAC values.
Electronegativity (Pauling)	0.79 – 3.98	Fr lowest, F highest.
Atomic Radius	30 – 260 pm	Covalent radii; varies with bonding.
Density (solid/liquid)	0.534 – 22.59 g/cm³	At or near room temperature.

Common Mistakes to Avoid

Confusing atomic mass with mass number of a specific isotope.
Using atomic radii for ions without adjustment.
Mis‑typing compound formulas (e.g., CO vs CO₂).
Assuming electronegativity values are absolute across scales (Pauling vs Mulliken).

Frequently Asked Questions

How accurate are the atomic masses?

Values are from IUPAC 2021 standard atomic weights, with 4–5 significant figures. For precise isotopic work, use specialized databases.

Why doesn't the electron configuration match my textbook?

Configurations shown are ground‑state, using the Aufbau principle. Exceptions (Cr, Cu, etc.) are noted. Some texts use noble‑gas core notation; we show full expanded notation.

Can I calculate molar mass for hydrates or complex ions?

The compound parser handles simple formulas only (e.g., CaCl₂). For hydrates like CuSO₄·5H₂O, enter CuSO4H10O5 (but note this changes the formula). For ions, omit charges.

What are the safety implications of using this data?

This is reference data only. Always consult SDS for handling, toxicity, flammability, and reactivity. Never rely solely on atomic properties for safety decisions.

Why is density missing for some elements?

Density is temperature‑dependent and may not be defined for gases at STP or for synthetic elements with no stable solid phase. We show common phase at 20°C where available.

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Periodic Table Quick Lookup

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