#### Quantum Mechanical Model of Atom Important Questions

11th Standard

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Chemistry

Time : 01:00:00 Hrs
Total Marks : 50
5 x 1 = 5
1. The energies E1and E2 of two radiations are 25 eV and 50 eV respectively. The relation between their wavelengths ie $\lambda$1 and$\lambda$2 will be

(a)

$\frac { { \lambda }_{ 1 } }{ { \lambda }_{ 2 } } =1$

(b)

${ \lambda }_{ 1 }=2{ \lambda }_{ 2 }$

(c)

${ \lambda }_{ 1 }=\sqrt { 25\times 50{ \lambda }_{ 2 } }$

(d)

$2{ \lambda }_{ 1 }={ \lambda }_{ 2 }$

2. For d-electron, the orbital angular momentum is

(a)

$\frac { \sqrt { 2 } h }{ 2\pi }$

(b)

$\\ \frac { \sqrt { 2h } }{ 2\pi }$

(c)

$\frac { \sqrt { 2\times 4 } h }{ 2\pi }$

(d)

$\frac { \sqrt { 2\times 4 } h }{ 2\pi }$

3. The subsidiary quantum number decides ______

(a)

the shape of the orbital

(b)

the orientation of the orbital

(c)

energy level of the orbital

(d)

the spin of the electron

4. Which of the following configuration is correct for iron?

(a)

1s22s22p63s23p64s23d7

(b)

1s22s22p63s23p64s23d6

(c)

1s22s22p63s23p63d7

(d)

1s22s22p63s23p64s23d7

5. How many electrons in an atom with atomic number 105 can have (n + I) = 8 ?

(a)

30

(b)

17

(c)

15

(d)

unpredictable

6. 5 x 2 = 10
7. The stabilisation of a half filled d - orbital is more pronounced than that of the p-orbital why?

8. Which quantum number reveal information about the shape, energy, orientation and size of orbitals?

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

10. Write the values of four quantum numbers present in the last electron in, an atom having the electronic configuration
(i) 1s2 2s2 2p1
(ii) 1s2 2s2 2p6 3s2 3p2.

11. How many electrons in sulphur (z = 16) can have n + I = 3?

12. 5 x 3 = 15
13. Which quantum accounts for the orientation of the electron orbital?

14. How many electrons can have s+ 1/2 in a d-subshell?

15. Explain briefly the time independent schrodinger wave equation?

16. Describe the Aufbau principle

17. Determine the values of all the four quantum numbers of the 8th electron in O- atom and 15th electron in CI atom and the last electron in chromium.

18. 4 x 5 = 20
19. What is the de Broglie wavelength (in cm) of a 160g cricket ball travelling at 140 Km hr-1.

20. Suppose that the uncertainty in determining the position of an electron in an orbit is 0.6 $\mathring{A}$ . What is the uncertainty in its momentum

21. Explain about (i) Magnetic quantum number (ii) Spin quantum number

22. Explain about the shape of orbitals.