#### Quantum Mechanical Model of Atom Important Questions

11th Standard

Reg.No. :
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Chemistry

Time : 01:00:00 Hrs
Total Marks : 50
10 x 1 = 10
1. The energy of light of wavelength 45 nm is

(a)

6.67 x 1015J

(b)

6.67 x 1011J

(c)

4.42 x 10-18J

(d)

4.42 x 10-15J

2. 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)

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

3. Splitting of spectral lines in an electric field is called

(a)

Zeeman effect

(b)

Shielding effect

(c)

Compton effect

(d)

Stark effect

4. The electronic configuration of Eu (Atomic no. 63) Gd (Atomic no. 64) and Tb (Atomic no. 65) are

(a)

[Xe] 4f6 5d' 6s2, [Xe] 4f7 Sd1 6s2 and [Xe] 4f8  5d1 6s2

(b)

[Xe] 4f7 , 6s2, [Xe] 4f7 5d1 6s2 and [Xe] 4f9 6s2

(c)

[Xe] 4f7 ,6s2, [Xe] 4f7 6s2 and [Xe] 4f7 5d1 6s2

(d)

[Xe] 4fSd1 6s2, [Xe] 4f7 5d1 6s2 and [Xe] 4f9 6s2

5. Which of the following pairs of d-orbitals will have electron density along the axes ?

(a)

dz2, dxz

(b)

dxz, dyZ

(c)

dz2, dx2-y2

(d)

dxy ,dx2-y2

6. The number of nodes in s orbital of any energy level is equal to

(a)

n

(b)

2n2

(c)

n-1

(d)

n-2

7. How many nodes are possible for 2s orbital?

(a)

1

(b)

2

(c)

3

(d)

zero

8. As per Aufbau principle, arrange the orbitals in increasing order of energy

(a)

4p > 4d > 5s > 5p

(b)

4p < 4d < 5s < 5p

(c)

4d < 4p < 5s < 5p

(d)

4p < 5s < 4d < 5p

9. What is the maximum numbers of electrons that can be associated with the following set of quantum numbers? n = 3, I = 1 and m =-1

(a)

4

(b)

6

(c)

2

(d)

= 10

10. The total number of orbitals associated with the principal quantum number n = 3 is

(a)

9

(b)

8

(c)

5

(d)

7

11. 5 x 2 = 10
12. How many orbitals are possible for n =4?

13. How many radial nodes for 2s, 4p, 5d and 4f orbitals exhibit? How many angular nodes

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

15. Write a note on Thomson's plum pudding model of an atom.

16. What did Rutherford's alpha ray scattering experiment prove

17. 5 x 3 = 15
18. An electron a proton which one will have a higher velocity to produce matter waves of the same wavelength? Explain it

19. Explain why the uncertainty principle is significant only for the motion of sub-atomic particles but is negligible for the macroscopic objects?

20. State and explain pauli's exclusion principle

21. Explain briefly the time independent schrodinger wave equation?

22. Describe the Autbau principle

23. 3 x 5 = 15
24. Enlist the postulates of Bohr's atom model.

25. By applying Bohr's postulates, arrive at the radius of nth orbit for hydrogen like atom

26. An ion with mass number 37 possesses unit negative charge. If the ion contains 11.1% more neutrons than electrons, Find the symbol of the ion.