⚛️ THE BOHR MODEL
PAGE 1 OF 5, PLANETS AROUND A NUCLEUS
THE CLASSIC PICTURE
ELECTRONS LIKE TINY PLANETS
Before quantum clouds, textbooks drew atoms as miniature solar systems. A tiny positive nucleus sat at the center, and electrons raced around it on circular tracks, the way planets orbit the Sun. That picture is the Bohr model, published by Danish physicist Niels Bohr in 1913. It was not just a cartoon. Bohr's rules explained why hydrogen gas glows in sharp colored lines when heated or sparked, and why atoms do not collapse even though opposite charges attract. The model was later replaced by quantum mechanics, but it was the first successful story of how light and matter talk to each other at the atomic scale.
⚛️ 1913 BREAKTHROUGH
Niels Bohr built on Rutherford's nuclear atom and Planck's quantum idea. He proposed that electrons occupy only certain allowed orbits, not any path they like.
ORBIT!
NUCLEUS
➕ Positive charge at the center
🪨 Almost all the atom's mass
📏 Tiny compared with electron orbits
🪨 Almost all the atom's mass
📏 Tiny compared with electron orbits
ELECTRONS
➖ Negative charge in motion
🪐 Drawn as circular orbits
🎯 Only certain radii allowed
🪐 Drawn as circular orbits
🎯 Only certain radii allowed