11th Standard Chemistry Quantum Mechanical Model of Atom English Medium Free Online Test One Mark Questions with Answer Key 2020 - 2021

11th Standard

Reg.No. :
•
•
•
•
•
•

Chemistry

Time : 00:20:00 Hrs
Total Marks : 20

Answer all the questions

20 x 1 = 20
1. According to the Bohr Theory, which of the following transitions in the hydrogen atom will give rise to the least energetic photon?

(a)

n = 6 to n = 1

(b)

n = S to n = 4

(c)

n = S to n = 3

(d)

n = 6 to n = S

2. Based on equation E = $-2.178\times { 10 }^{ -18 }J\left( \frac { { Z }^{ 2 } }{ { n }^{ 2 } } \right)$certain conclusions are written. Which of them is not correct?

(a)

Equation can be used to calculate the change in energy when the electron changes orbit

(b)

For n = I, the electron has a more negative energy than it does for n = 6 which means that the electron is more loosely bound in the smallest allowed orbit

(c)

The negative sign in equation simply means that the energy of electron bound to the nucleus is lower than it would be if the electrons were at the infinite distance from the nucleus.

(d)

Larger the value of n, the larger is the orbit radius.

3. The maximum number of electrons in a sub shell is given by the expression

(a)

2n2

(b)

21+ I

(c)

41+ 2

(d)

none of these

4. Consider the following statements and pick the incorrect statement(s).
1.Schrodinger wave equation is used to determine the probability of finding a electron at a given point in space.
2.The energy of a electron at infinity is positive
3.Angular momentum quantum number gives information regarding subshells.

(a)

1&3

(b)

only 1

(c)

only 2

(d)

1,2 & 3

5. 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

6. The electronic configuration of copper is ______

(a)

[Ar]4s23d9

(b)

[Ar]4s13d10

(c)

[Ar]4s03d10

(d)

All

7. Shape of an orbital is given by

(a)

Principal quantum number

(b)

Spin quantum number

(c)

Azimuthal quantum number

(d)

Magnetic quantum number

8. Electron density in the yz plane of 3dxy-y2 orbital is

(a)

zero

(b)

0.50

(c)

0.75

(d)

0.90

9. Match the quantum numbers with the information provided by these.

 Quantum number Information Provided A Principal quantum number 1 orientation of the orbital B Azimuthal quantum number 2 energy and size of orbital C Magnetic quantum number 3 spin of electron D Spin quantum number 4 shape of the orbital
(a)
 A B C D 1 2 3 4
(b)
 A B C D 2 4 3 1
(c)
 A B C D 3 2 4 1
(d)
 A B C D 4 3 2 1
10. Which of the following does not represent the mathematical expression for the Heisenberg uncertainty principle?

(a)

$\triangle x.\triangle p\ge \frac { h }{ 4\pi }$

(b)

$\triangle x.\triangle v\ge \frac { h }{ 4\pi m }$

(c)

$\triangle E.\triangle t\ge \frac { h }{ 4\pi }$

(d)

$\triangle E.\triangle x\ge \frac { h }{ 4\pi }$

11. J. J. Thomson's cathode ray experiment revealed that atoms consist of

(a)

electrons

(b)

protons

(c)

neutrons

(d)

photons

12. Consider the following statements
1.$\lambda$ .= h / mv is valid only when the particle travels at speed much less than the speed of light.
2. Einstein's mass-energy relationship is E=mc2
3. The angular momentum (mvr) ofthe electron must be equal to an integral multiple of h/4$\pi$ . Which of the following statementts) given above is/ are correct?

(a)

1&3

(b)

Only 1

(c)

1 & 2

(d)

1, 2 & 3

13. Using s, p, d, f notations, describe the orbital with the following quantum numbers n = 2, I = 1.

(a)

2s

(b)

1s

(c)

2p

(d)

1p

14. How many neutrons and protons respectively are present  in the 6C13 nuclei?

(a)

6, 13

(b)

6, 7

(c)

13,6

(d)

7,6

15. Almost the entire mass of an atom is concentrated in the ----

(a)

proton

(b)

electrons

(c)

neutrons

(d)

nucleus

16. The radius of nucleus is approximately __ times smaller than the radius of atom.

(a)

1,00,000

(b)

5,000

(c)

10,000

(d)

200

17. When $\alpha$- rays strike a thin gold foil then,

(a)

most of the $\alpha$- rays do not pass through the gold foil.

(b)

most of the $\alpha$- rays get deflected back.

(c)

most of the $\alpha$ rays get deflected through small angles.

(d)

most of the $\alpha$- rays pass through without any deviation.

18. 6C14 and 7N14 are

(a)

isotones

(b)

isoelectronic

(c)

isobars

(d)

isotopes

19. Dual character of an electron was explained by

(a)

Bohr

(b)

Heisenberg

(c)

de-Broglie

(d)

Pauli

20. Assertion: Number of radial and angular nodes for 3p orbital are 1, 1 respectively.
Reason: Number of radial and angular nodes depends only on principal quantum number.

(a)

both assertion and reason are true and reason is the correct explanation of assertion.

(b)

both assertion and reason are true but reason is not the correct explanation of assertion.

(c)

assertion is true but reason is false

(d)

both assertion and reason are false