Understand the myriad changes in matter from one atom.
118 chemical elements 87reaction equation free query · traceable source
currently contains 118 elements and selected inorganic and organic reactions. The number of known chemical reactions continues to grow, and this library is not an exhaustive database of all known reactions.
The atomic number is equal to the number of protons and determines the identity of the element. The horizontal direction is the period and the vertical direction is the group; main group elements of the same group often have similar outermost electronic structures. The s, p, d, and f regions reflect electron filling and orbital types; this table places the lanthanide series and the actinide series independently for easier reading. The boundaries between the third group and the f region have different conventions in different tables.
Oxidation state is a formal charge accounting tool and is not equivalent to the true charge of the atom. The determination of valence electrons in transition metals depends on the bonding context, so this library provides electron configurations and oxidation states without compressing valence electrons into a single value that is easy to misuse.
properties taken from PubChem periodic table snapshot (2026-10-04). Atomic weights may be reference values or representative isotope masses and cannot be considered exact constants for all samples; density, phase transition points, and phase states depend on temperature, pressure, and allotropes. The solidification of helium requires pressure. Some properties of radioactive and superheavy elements are predicted values, and missing items are marked as not included. Please check the original source and experimental conditions for precise calculations.
87balanced reactions · Browse element associations by atomic number
found 87reactions, display 18strips.
All modes are grouped by the element with the smallest atomic number in each reaction; select any element to find all reactions involving it. Equations only express stoichiometry and concepts, not experimental operation recipes.
01 · Hydrogen H Hydrogen
inorganic · redox
Water formation
Water formation
2H₂ + O₂ → 2H₂O
Applicable situations: Energy input can trigger a reaction
Hydrogen is oxidized and oxygen is reduced; the balance coefficient expresses the quantity relationship of substances, not the reaction rate.
The total reaction summarizes hydrogen evolution at the cathode and oxygen evolution at the anode. The actual electrolysis voltage is affected by overpotential and resistance.
Applicable situations: Industrial Catalytic Balance System
The reaction is jointly controlled by temperature, pressure and equilibrium composition, and is the basis for material balance of ammonia synthesis.
The
Applicable situations: Total quantitative formula for oxygenated water phase absorption
This is a net material relationship for a multi-step process and cannot be used as a substitute for mass transfer and kinetic models.
The coordinates of
The oxidation state of nitrogen increases from positive divalent to positive tetravalent, which is related to the chemistry of atmospheric nitrogen oxides.