02Class 11 Chemistry

Structure of Atom formulas

Bohr model, de Broglie and quantum number formulas for Structure of Atom. Many of these repeat in Class 12 Physics, so learn them once, well.

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All Chemistry formulas

Light and energy

Wave relation: $\displaystyle c = \nu\lambda$
Photon energy: $\displaystyle E = h\nu = \frac{hc}{\lambda}$
Photoelectric effect: $\displaystyle \tfrac12mv^2 = h\nu - h\nu_0$

Bohr model

Energy of the nth orbit: $\displaystyle E_n = -2.18\times10^{-18}\,\frac{Z^2}{n^2}\ \text{J}$
Radius: $\displaystyle r_n = 52.9\,\frac{n^2}{Z}\ \text{pm}$
Spectral lines: $\displaystyle \bar\nu = 109677\left(\frac{1}{n_1^2} - \frac{1}{n_2^2}\right)\ \text{cm}^{-1}$

Quantum mechanics

de Broglie wavelength: $\displaystyle \lambda = \frac{h}{mv}$
Heisenberg's uncertainty principle: $\displaystyle \Delta x\cdot\Delta p \ge \frac{h}{4\pi}$
Orbital angular momentum: $\displaystyle L = \sqrt{l(l + 1)}\,\frac{h}{2\pi}$
Nodes: $\displaystyle \text{radial} = n - l - 1, \quad \text{angular} = l$
Maximum electrons: $\displaystyle \text{in a shell} = 2n^2, \quad \text{in a subshell} = 2(2l + 1)$

Where students slip up

Ignoring exceptions like Cr and Cu, which have half-filled or fully filled d subshells.
Using the n + l rule without breaking ties. If n + l is equal, the lower n fills first.
Confusing the total number of nodes (n − 1) with radial nodes alone.

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