Chemical Bond Simulator
Visualise ionic & covalent bonds with animated Bohr atomic models — 21 real compounds, 37 elements
Select two elements then click Test Bond. The reaction engine checks if they can form an ionic or covalent compound.
Chemical Bonds Quiz
Test your knowledge of ionic and covalent bonding with 5 randomised questions covering bond types, valence electrons, electron transfer and sharing, and compound identification.
1 Overview
This simulator shows how atoms form chemical bonds using the Bohr atomic model. You can visualise both ionic bonds (electron transfer between metal and nonmetal) and covalent bonds (electron sharing between nonmetals). The tool includes 21 preset compounds (11 covalent + 10 ionic), a reaction engine covering 37 elements, and a 15-question quiz bank.
2 Simulate Mode
- Left panel — Build a Compound: Select any two elements from the 37-element grid (metals gold, non-metals teal, noble gases purple, metalloids grey). Click ⚗ Test Bond to validate and auto-launch the Bohr model animation.
- Right panel — Preset Compounds: Choose a bond type (Covalent / Ionic) and select a compound from the tabs, then click ▶ Simulate to watch the animation.
- After the animation, the Info Panel shows electron counts, bond data, and real-world facts.
- 📷 Export: Click the Export button (or right-click the canvas) to save the current frame as a PNG image.
- 🔊 Sound: Click the speaker icon to mute / unmute the bond-formation sound effects. Right-click the canvas to toggle the background grid.
3 Explore Mode
Browse educational cards about bonding concepts across four tabs: Overview (what bonds are, valence electrons, electronegativity, Bohr model), Covalent (single/double/triple bonds, polarity, lone pairs), Ionic (transfer mechanism, charge balance, crystal properties), and Comparison (formation, physical properties, conductivity, examples).
4 Quiz Mode
5 randomised multiple-choice questions per round drawn from a pool of 15. Topics include bond type identification, valence electrons, electron transfer, and electronegativity. Each answer shows a detailed explanation. The result screen colour-codes correct (✓) and incorrect (✗) answers so you know exactly what to review. Score 5/5 for ★★★.
Free Online Chemical Bond Simulator — Ionic & Covalent Bonding Visualised
This free chemistry simulator animates ionic and covalent bond formation using live Bohr atomic models. Watch electrons transfer or share in real time, build your own compounds from 37 elements, and test your knowledge with an interactive quiz — no login, no download, works on any device.
Why Do Atoms Form Chemical Bonds?
Atoms bond because doing so lowers their total energy and produces a more stable electron configuration. Most atoms aim to fill their outermost shell with 8 electrons — the octet rule — mimicking the stable configuration of noble gases like neon and argon. Hydrogen is the exception: its first shell holds only 2 electrons (the duet rule), so H₂, HCl, and H₂O all satisfy hydrogen with just 2 electrons.
What Is the Difference Between Ionic and Covalent Bonds?
The key difference is what happens to the electrons. In an ionic bond, a metal atom gives one or more electrons entirely to a nonmetal, creating oppositely charged ions that attract each other electrostatically (e.g., Na⁺ and Cl⁻ in table salt). In a covalent bond, two nonmetals share electrons equally or unequally, keeping the pair between both nuclei (e.g., the O–H bonds in water). Ionic compounds are typically hard crystalline solids with high melting points; covalent compounds are often gases, liquids, or soft solids at room temperature.
How Does Electronegativity Determine Bond Type?
Electronegativity (EN) measures how strongly an atom pulls electrons toward itself. The difference in EN between two bonded atoms predicts the bond type — a rule every chemistry student needs to know:
| EN Difference | Bond Type | Example | Character |
|---|---|---|---|
| > 1.7 | Ionic | NaCl (2.23), LiF (3.00) | Full electron transfer → ions formed |
| 0.5 – 1.7 | Polar Covalent | H₂O (1.24), HCl (0.96) | Unequal sharing → δ+/δ− dipole |
| < 0.5 | Nonpolar Covalent | H₂ (0.00), CH₄ (0.35) | Equal sharing → no dipole |
Fluorine (EN 3.98) is the most electronegative element; caesium (EN 0.79) is the least. The simulator highlights the EN difference for every compound and flags whether the bond is nonpolar, polar, or fully ionic.
What Are Single, Double, and Triple Covalent Bonds?
Bond order is the number of shared electron pairs between two atoms. More shared pairs means a shorter, stronger, and harder-to-break bond:
| Bond Order | Shared Pairs | Example | Bond Energy |
|---|---|---|---|
| Single | 1 pair (2 e⁻) | H₂, HCl, H₂O | ~200–500 kJ/mol |
| Double | 2 pairs (4 e⁻) | O₂, CO₂ | ~500–750 kJ/mol |
| Triple | 3 pairs (6 e⁻) | N₂ (945 kJ/mol) | ~800–1000 kJ/mol |
Why Do Ionic Compounds Conduct Electricity When Dissolved?
In solid form, ionic compounds lock their ions into a rigid crystal lattice — the ions cannot move, so no electric current flows. When dissolved in water or melted, the lattice breaks apart and the free ions (e.g., Na⁺ and Cl⁻) migrate through the solution, carrying charge and conducting electricity. This is why NaCl solution (saline) conducts, but solid NaCl does not. The simulator animates this electron-transfer process step by step so you can see exactly which electrons move and why.
How Does the Bohr Model Visualise Chemical Bonding?
The Bohr model (1913) places electrons in discrete shells around the nucleus: shell 1 holds 2 electrons, shell 2 holds 8, shell 3 holds up to 18. While modern quantum mechanics describes electron probability clouds rather than fixed orbits, the Bohr model remains the gold standard for teaching bonding because it makes valence electrons, electron transfer, and electron sharing visually obvious. Every element in this simulator is rendered as a real-time animated Bohr model — you can watch valence electrons leave the sodium atom and arrive on the chlorine atom, or see shared electron pairs oscillating between two oxygen nuclei in O₂.
How to Use This Chemical Bond Simulator
- Preset Simulate mode — select Covalent or Ionic, choose a compound (H₂, NaCl, Al₂O₃…), click Simulate and watch the full animated Bohr model sequence.
- Build a Compound — pick any two of 37 elements from the periodic grid and click Test Bond. The built-in reaction engine checks valence electrons, electronegativity, and element types; it either launches the animation or explains exactly why the combination is invalid (noble gas, metal–metal alloy, etc.).
- Explore mode — read concept cards on bonding fundamentals, polarity, lone pairs, and property comparisons.
- Quiz mode — answer 5 randomised questions from a 15-question bank; get instant feedback and a colour-coded result card showing what to review.
Curriculum Alignment — GCSE, A-Level, AP & IB Chemistry
This simulator directly supports the chemical bonding topic across major curricula: GCSE Chemistry (ionic and covalent bonding, dot-and-cross diagrams, properties of ionic compounds), A-Level Chemistry (electronegativity, bond polarity, lattice energy, molecular shapes), AP Chemistry (Unit 2: Molecular and Ionic Compound Structure, bond order and energy), and IB Chemistry (Topic 4: Chemical Bonding and Structure). Teachers can use the live canvas in class as an animated alternative to static diagrams, and students can self-study at home or on a tablet with no installation required.
Who Uses This Chemistry Simulator?
Students at GCSE, A-Level, AP, IB, and vocational (BTEC/TVET) level use it to visualise content that is abstract in textbooks. Chemistry teachers use it as a projected demonstration — the full-screen canvas and step-by-step animation replace printed diagrams in lessons on ionic bonding, covalent bonding, and electronegativity. Tutors use the Build-a-Compound engine to challenge students with unfamiliar element pairs. Self-learners preparing for resit exams use the quiz to identify knowledge gaps quickly. The tool is completely free, requires no account, and works on desktop, laptop, and iPad.
Explore Related Free Chemistry & Science Simulators
Deepen your chemistry and physics knowledge with other free simulators on MechSimulator. Test acid and alkali reactions with the Litmus Paper Test Virtual Lab. Explore how gases behave under pressure and temperature with the Boyle’s Law Simulator, Charles’ Law Simulator, and Ideal Gas Law Simulator. Understand heat flow with the Heat Transfer Simulator, or explore electrical fundamentals with the Ohm’s Law Simulator. All tools are free, browser-based, and require no signup or installation.