#### Quantum Mechanical Model of Atom Book Back Questions

11th Standard

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Chemistry

Time : 00:45:00 Hrs
Total Marks : 30
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. Two electrons occupying the same orbital are distinguished by

(a)

azimuthal quantum number

(b)

spin quantum number

(c)

magnetic quantum number

(d)

orbital quantum number

3. 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)

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

4. 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

5. If n = 6, the correct sequence for filling of electrons will be,

(a)

ns $\rightarrow$ (n-2)f $\rightarrow$ (n-l)d $\rightarrow$ np

(b)

ns $\rightarrow$ (n - I) d $\rightarrow$ (n - 2) f $\rightarrow$ np

(c)

ns $\rightarrow$ (n-2)f $\rightarrow$np $\rightarrow$ (n-l)d

(d)

none of these are correct

6. 3 x 2 = 6
7. How many orbitals are possible for n =4?

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

9. An atom of an element contains 35 electrons and 45 neutrons. Deduce
(i) the number of protons
(ii) the electronic configuration for the element
(iii) All the four quantum numbers for the last electron

10. 3 x 3 = 9
11. State and explain pauli's exclusion principle

12. Calculate the uncertainty in position of an electron, if Av = 0.1% and $\upsilon$ = 2.2 x 106 ms-1.

13. 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.

14. 2 x 5 = 10
15. Protons can be accelerated in particle accelerators. Calculate the wavelength (in A)of such accelerated proton moving at 2.85 x 108 ms-1 (the mass of proton is 1.673x10-27 Kg).

16. 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