Bohr's Model of the Atom

Quantized Orbits: Electrons can only orbit the nucleus in specific 'allowed' orbits without radiating energy, which maintains the atom's stability.

Energy Level Capacity: Each energy level has a maximum capacity for electrons; for instance, the first level can hold up to 2, while the second and third can hold up to 8 each.

Energy-Distance Relationship: The energy of an electron is directly related to its distance from the nucleus, expressed as $E \propto r$, where $E$ is energy and $r$ is the orbital radius.

Angular Momentum: Bohr postulated that the angular momentum of an electron is quantized in integral multiples of $\frac{h}{2\pi}$, where $h$ is Planck's constant.

Absorption: When an electron absorbs electromagnetic radiation (like light or heat), it gains energy and 'jumps' to a higher, more distant energy level.

Excited State: An electron in a higher energy level is in an unstable 'excited state' and will naturally seek to return to a lower, more stable level.

Emission: As the electron falls back to a lower energy level, it releases the excess energy in the form of a photon (a wave of electromagnetic radiation).

Photon Energy: The energy of the emitted or absorbed radiation is exactly equal to the difference in energy between the two levels: $\Delta E = E_{final} - E_{initial}$.

The 'Spiral' Error: Students often forget that Bohr's model was specifically designed to solve the problem of electrons spiraling into the nucleus by introducing fixed orbits.

Between Levels: A common misconception is that electrons 'travel' through the space between orbits; in quantum terms, they disappear from one and appear in another (quantum leap).

Capacity Confusion: Do not assume all shells have the same capacity; the 1st shell is unique with its limit of 2 electrons.

Radiation Source: Remember that radiation is only emitted during a transition, not while the electron is simply moving within its stable orbit.