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#### Quantum Mechanical Model of Atom Two Marks Question

11th Standard

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Chemistry

Time : 00:45:00 Hrs
Total Marks : 30
15 x 2 = 30
1. The stabilisation of a half filled d - orbital is more pronounced than that of the p-orbital why?

2. How many orbitals are possible for n =4?

3. How fast must a 54g tennis ball travel in order to have a de Broglie wavelength that is equal to that of a photon of green light 5400$\overset { 0 }{ A }$ ?

4. Give the electronic configuration of Mn2+ and Cr3+

5. What is the charge and mass of an electron?

6. What is the difference between atomic mass and mass number?

7. Bring out the similarities and dissimilarities between a 1s and 2s orbital.

8. The ground state electronic configurations listed below here are incorrect. Explain what mistakes have been made in each and correct the electronic configuration.
(i) Al = 1s2 2s2 2p4 3s2 3p6 .
(ii) B = 1s2 2s2 2p5
(iii) F = 1s2 2s2 2p5.

9. What is the angular momentum of an electron in (i) 2s orbital (ii) 4f orbital?

10. The kinetic energy of a subatomic particle is 5.58 x 10-25 J. Calculate the frequency of the particle wave. (Planck's constant h = 6.626 x 10-34 kg m2 s-1)

11. Which is the actual configuration of Cr ( Z = 24). Why?

12. Explain how matter has dual character?

13. How many orbitals are possible in the 3rd energy level?

14. Energy of an electron in hydrogen atom in ground state is -13.6 eV. What is the energy of the electron in the third excited state?

15. Mention the shape of s, p, d orbitals.