Bohr's Model — Prelims Strategy

Prelims Strategy

To excel in NEET questions on Bohr's Model, a systematic approach is essential. First, thoroughly memorize Bohr's three postulates and the key formulas for radius ($r_n = 0.529 \frac{n^2}{Z} \text{ Å}$), energy ($E_n = -13.

6 rac{Z^2}{n^2} ext{ eV}$), and velocity ($v_n = 2.18 imes 10^6 rac{Z}{n} ext{ m/s}$). Understand the proportionality relationships ($r propto n^2/Z$,$E propto Z^2/n^2$,$v propto Z/n$) as these are frequently tested in ratio problems, allowing for faster calculations without needing to plug in constants.

For numerical problems, always identify the atomic number ($Z$) and the principal quantum number ($n$) correctly. Pay close attention to units (eV, Å, m/s). When dealing with spectral lines, remember the Rydberg formula (rac{1}{lambda} = R_H Z^2 left( \frac{1}{n_1^2} - \frac{1}{n_2^2} \right)) and the common series (Lyman, Balmer, Paschen) along with their respective $n_1$ values and spectral regions.

For conceptual questions, focus on the limitations of Bohr's model (e.g., failure for multi-electron atoms, Zeeman effect) and how it differs from Rutherford's model. Practice identifying trap options that might use incorrect proportionality or misinterpret postulates.

Time management is key; quick recall of formulas and proportionalities will save valuable seconds.