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A real probability cloud for the hydrogen-like orbitals, computed from the exact solutions of the Schrödinger equation — correct radial functions (associated Laguerre polynomials) and real spherical harmonics. In 3-D, every dot is a Monte-Carlo sample drawn from |ψ|², so the dot density literally is the probability density. The two hues show the sign (phase) of ψ.

⏸ Spin

Alkali Alkaline Earth Transition Post-transition Metalloid Nonmetal Halogen Noble Gas Lanthanide Actinide ✕ Clear

Known Quantity

Enter each element’s percent by mass. They should total ≈100%.

+ Add Element

Find Unit Moles Grams

M = n/V — Leave one field blank to solve for it

M₁V₁ = M₂V₂ — Leave one field blank to solve for it

m = moles solute / kg solvent

PV = nRT — Leave one blank to solve for it. R = 8.314 J/mol·K

P₁V₁ = P₂V₂ — Leave one blank to solve for it

V₁/T₁ = V₂/T₂ — Leave one blank (T must be in Kelvin)

P₁/T₁ = P₂/T₂ — Leave one blank (T must be in Kelvin)

P₁V₁/T₁ = P₂V₂/T₂ — Leave one blank

Rate₁/Rate₂ = √(M₂/M₁) — Leave one blank

q = mcΔT — Leave one blank to solve for it

Add enthalpies of component reactions. Multiply by factor, check "Reverse" to negate ΔH.

+ Add Reaction Calculate Total ΔH

ΔH°rxn = Σ ΔH°f(products) − Σ ΔH°f(reactants)

Calculate ΔH°rxn

Balanced Equation Generate ICE Table

Kc = [products]^coef / [reactants]^coef

Calculate Kc

Compare Q to Kc to predict direction of shift

Calculate Q and Compare

Ionic Compound Formula Calculate

Chemical Formula or Ion Determine Oxidation States

Half-Reaction (unbalanced) Medium Acidic solution (H⁺/H₂O) Basic solution (OH⁻/H₂O) Balance Half-Reaction

Value

Enter a Number

Enter Number or Scientific Notation

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Reveals the Diagnostics panel (in-browser self-tests of every calculator).

Preferences are saved on this device.

Runs the calculation engines against a battery of known-answer self-tests, directly in your browser. This is the visible health check for Valence — molar mass, the rebuilt empirical-formula pipeline, the molecular-graph Lewis engine (including complex molecules like ethanol and acetic acid), per-atom VSEPR, and precipitation logic.

Shows the electron configuration — which orbitals an element's electrons fill (the ↑↓ box notation). For the 3-D shape of each orbital, see Orbital Clouds →

This tool computes bonds, lone pairs and formal charges from a molecule's connectivity — it doesn't memorize answers. It's in beta while edge cases are worked out.