# Important Formulas of Structure of Atom Class 11, JEE, NEET

Here is the list of all the Important Formulas of Structure of Atom Class 11. This formula list is very important to revice before your JEE Main, Advanced or NEET Exam.

## All Formulas of Structure of Atom Class 11

Structure of Atom is First chapter in Chemistry Class 11. Here is the detailed list of all the formulas of this chapter.

1. Estimation of closest distance of approach (derivation) of $\alpha$-particle : $\quad R =\frac{4 KZe ^{2}}{ m _{\alpha} V _{\alpha}^{2}}$

2. The radius of a nucleus: $\quad R = R _{0}( A )^{1 / 3}$ cm

3. Planck’s Quantum Theory: $\quad$ Energy of one photon $= h v=\frac{ hc }{\lambda}$

4. Photoelectric Effect: $\quad \text { hv }=h v_{0}+\frac{1}{2} m_{e} v^{2}$

5. Bohr’s Model for Hydrogen like atoms:

• $mvr = n \frac{ h }{2 \pi}$ (Quantization of angular momentum)
• $E _{ n }=-\frac{ E _{1}}{ n ^{2}} z ^{2}=2.178 \times 10^{-18} \frac{ z ^{2}}{ n ^{2}} J / atom =13.6 \frac{ z ^{2}}{ n ^{2}} eV ; \quad E _{1}=\frac{-2 \pi^{2} me ^{4}}{ n ^{2}}$
• $r_{n}=\frac{n^{2}}{z} \times \frac{n^{2}}{4 \pi^{2} e^{2} m}=\frac{0.529 \times n^{2}}{z} A$
• $v=\frac{2 \pi ze ^{2}}{ nh }=\frac{2.18 \times 10^{6} \times z }{ n } m / s$

6. De-Broglie wavelength: $\lambda=\frac{ h }{ mc }=\frac{ h }{ p }(\text { for photon })$

7. Wavelength of emitted photon: $\frac{1}{\lambda}=\bar{v}=R Z^{2}\left(\frac{1}{n_{1}^{2}}-\frac{1}{n_{2}^{2}}\right)$

8. Number of photons emitted by a sample of H atom: $\frac{\Delta n(\Delta n+1)}{2}$

9. Heisenberg’s uncertainty principle: $\Delta x . \Delta p>\frac{h}{4 \pi}$ or $m \Delta x \cdot \Delta v \geq \frac{ h }{4 \pi}$ or $\Delta x . \Delta v \geq \frac{h}{4 \pi m}$

10. Quantum Numbers:

• Principal quantum number $(n)=1,2,3,4 \ldots . .$ to $\infty .$
• Orbital angular momentum of electron in any orbit $=\frac{ nh }{2 \pi}$
• Azimuthal quantum number $(\ell)=0,1, \ldots \ldots$ to $(n-1)$
• Number of orbitals in a subshell $=2 \ell+1$
• Maximum number of electrons in particular subshell $=2 \times(2 \ell+1)$
• Orbital angular momentum L = $\frac{ h }{2 \pi} \sqrt{\ell(\ell+1)}=\hbar \sqrt{\ell(\ell+1)}$
$\left[\hbar=\frac{h}{2 \pi}\right]$

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## Class 11 Chemistry Formulas

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