Atom Builder

Ready to Experiment?

Create your own atoms from scratch! Add protons, neutrons, and electrons to see how they combine to form different elements.

What You'll Learn

• How protons determine the element
• The role of neutrons in isotopes
• How electrons create ions
• The relationship between atomic structure and the periodic table

How to Use

1. Add Protons: Click the proton button to add protons to the nucleus
2. Add Neutrons: Add neutrons to create different isotopes
3. Add Electrons: Balance electrons to create neutral atoms or ions
4. Observe: Watch the element name, symbol, and properties update

Try These Challenges

• Build a hydrogen atom (simplest element)
• Create a carbon-12 atom (6 protons, 6 neutrons, 6 electrons)
• Make a sodium ion (Na+) by removing one electron
• Build an isotope: Carbon-14 (6 protons, 8 neutrons)

Key Concepts

Atomic Number

The number of protons defines which element you have. Change the protons, change the element!

Isotopes

Atoms of the same element with different numbers of neutrons. Carbon-12 and Carbon-14 are both carbon, just with different neutrons.

Ions

When electrons don't equal protons, the atom has a charge. More electrons = negative ion. Fewer electrons = positive ion.