🔬 Science Grades 5–12

Interactive Periodic Table

Tap any element to see its details. Color shows the family. Use the search to find an element by name or symbol, and the molar mass calculator for chemistry problems.

Learn How it works

Atomic number (top) = number of protons. It defines the element.
Atomic mass (bottom) is the average mass of an atom in atomic mass units (u). It is also the molar mass in grams per mole.
Periods are rows: elements in the same row have the same number of electron shells. Groups are columns: elements in the same group have the same number of valence electrons and react in similar ways.
Metals are on the left, nonmetals on the upper right, and metalloids along the staircase between them.

Examples See it done

Molar mass of water, H₂O: 2 × 1.008 (H) + 16.00 (O) = 18.02 g/mol.

Valence electrons: sodium (Na) is in group 1, so it has 1 valence electron and tends to lose it, forming Na⁺.

Try it Periodic table

Tap an element to see its details.

Molar mass calculator

Try C6H12O6, Ca(OH)2, NaCl

Practice Check yourself

Answer, then tap Check. You get an explanation either way.

How many protons does carbon (atomic number 6) have?
Elements in the same column (group) have the same number of… neutrons valence electrons shells
Use the calculator: what is the molar mass of CO₂ to one decimal place (g/mol)?
Which family is unreactive because its outer shell is full? Alkali metals Halogens Noble gases