11th Chemistry - Book Back Answers - Unit 2 - English Medium Guides

 

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Tamil Nadu Board 11th Standard Chemistry - Unit 2: Book Back Answers and Solutions

    This post covers the book back answers and solutions for Unit 2 – Chemistry from the Tamil Nadu State Board 11th Standard Chemistry textbook. These detailed answers have been carefully prepared by our expert teachers at KalviTips.com.

    We have explained each answer in a simple, easy-to-understand format, highlighting important points step by step under the relevant subtopics. Students are advised to read and memorize these subtopics thoroughly. Once you understand the main concepts, you’ll be able to connect other related points with real-life examples and confidently present them in your tests and exams.

    By going through this material, you’ll gain a strong understanding of Chemistry Unit 2 along with the corresponding book back questions and answers (PDF format).

Question Types Covered:

• 1 Mark Questions: Choose the correct answer, Fill in the blanks, Identify the correct statement, Match the following 
• 2 Mark Questions: Answer briefly 
• 3, 4, and 5 Mark Questions: Answer in detail

All answers are presented in a clear and student-friendly manner, focusing on key points to help you score full marks.

All the best, Class 11 students! Prepare well and aim for top scores. Thank you!

Unit 2:Quantum Mechanical Model of Atom

I. Choose the best answer.

1. Electronic configuration of species M²+ is 1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁶  and its atomic weight is 56. The number of neutrons in the nucleus of species M is
a) 26
b) 22
c) 30
d) 24
Answer Key:
c) 30

2. The energy of light of wavelength 45 nm is

a) 6.67x10¹⁵J

b) 6.67x10¹¹J

c) 4.42 x10^-18J

d) 4.42x10^-15J

Answer Key:
c) 4.42 x10^-18J

3. 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) ${\mathrm{\lambda }}_1=\sqrt{25\mathrm{X}50{\mathrm{\lambda }}_2}$
d)$\mathrm{ 2}{\mathrm{\lambda }}_1={\mathrm{\lambda }}_2$
Answer Key:
b) ${\lambda }_1=2{\lambda }_2$

4. Splitting of spectral lines in an electric field is called 
a) Zeeman effect
b) Shielding effect
c) Compton effect
d) Stark effect
Answer Key:
d) Stark effect

5. Based on equation E=-2.178 x10^-18J , 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 = 1 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.
Answer Key:
b) For n = 1 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

6. 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 n = 1
b) n = 5 n = 4
c) n = 5 n = 3
d) n = 6 to n = 5
Answer Key:
d) n = 6 to n = 5

7. Assertion: The spectrum of He is expected to be similar to that of hydrogen
Reason: He is also one electron system.
(a) If both assertion and reason are true and reason is the correct explanation of assertion.
(b) If both assertion and reason are true but reason is not the correct explanation of assertion.
(c) If assertion is true but reason is false
(d) If both assertion and reason are false
Answer Key:
(a) If both assertion and reason are true and reason is the correct explanation of assertion.

8. Which of the following pairs of d-orbitals will have electron density along the axes ? (NEET Phase - II)
a) ${\mathrm{d}}_{{\mathrm{z}}^2},{\mathrm{d}}_{\mathrm{xz}}$
b) ${\mathrm{d}}_{\mathrm{xz,}}{\mathrm{d}}_{\mathrm{yz}}$
c) ${\mathrm{d}}_{{\mathrm{z}}^2}{\mathrm{,d}}_{{\mathrm{x}}^2-{\mathrm{y}}^2}$
d) ${\mathrm{d}}_{\mathrm{xy,}}{\mathrm{d}}_{{\mathrm{x}}^2-{\mathrm{y}}^2}$
Answer Key:
c) ${\mathrm{d}}_{{\mathrm{z}}^{\mathrm{2,}}}{\mathrm{d}}_{{\mathrm{x}}^2-{\mathrm{y}}^2}$

9. 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
Answer Key:
b) spin quantum number

10. The electronic configuration of Eu (Atomic no. 63) Gd (Atomic no. 64) and Tb (Atomic no. 65) are (NEET - Phase II)

a) [Xe] 4f⁶ 5d¹ 6s²,[Xe] 4f⁷ 5d¹ 6s² and [Xe] 4f⁸ 5d¹6s²

b) [Xe] 4f ⁷,6s², [Xe] 4f⁷ 5d¹ 6s² and [Xe] 4f⁹ 6s²

c) [Xe] 4f⁷, 6s², [Xe]4f⁸ 6s² and [Xe] 4f⁸ 5d¹ 6s²

d) [Xe] 4f⁶ 5d¹ 6s², [Xe] 4f⁷ 5d¹ 6s² and [Xe] 4f⁹ 6s²

Answer Key:
b) [Xe] 4f ⁷,6s², [Xe] 4f⁷ 5d¹ 6s² and [Xe] 4f⁹ 6s²

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

a) 2n²

b) 2l + 1
c) 4l + 2
d) none of these
Answer Key:
c) 4l + 2

12. For d-electron, the orbital angular momentum is
a)
b) $\frac{\sqrt{2\mathrm{h}}}{2\mathrm{\pi }}$
c) $\frac{\sqrt{2\mathrm{x}4}\mathrm{h}}{2\mathrm{\pi }}$
d) $\frac{\sqrt{6}\mathrm{h}}{2\mathrm{\pi }}$
Answer Key:
d) $\frac{\sqrt{6}\mathrm{h}}{2\mathrm{\pi }}$

13. What is the maximum numbers of electrons that can be associated with the following set of quantum numbers? n = 3 l = 1 and m = - 1
a) 4
b) 6
c) 2
d )10
Answer Key:
c) 2

14. 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 as-sertion.
(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
Answer Key:
(c) assertion is true but reason is false

15. The total number of orbitals associated with the principal quantum number n = 3 is
a) 9
b) 8
c) 5
d) 7
Answer Key:
a) 9

16. If n = 6 the correct sequence for filling of electrons will be,
a) ns → (n - 2) f → (n - 1)d →np
b) ns→  (n - 1)d → (n - 2)f → np
c) ns → (n - 2) f → np → (n - 1)d
d) none of these are correct
Answer Key:
a) ns→  (n - 2) f → (n - 1)d →np

17. Consider the following sets of quantum numbers:
        n     l     m      s
i)    3     0     0      +1/2

ii)   2    2      1      -1/2
iii)  4    3     -2     +1/2

iv)  1     0     -1     +1/2

v)    3    4       3     -1/2

 

Which of the following sets of quantum number is not possible?
a) (i), (ii), (iii) and (iv)
b) (ii), (iv) and (v)
c) (i) and (iii)
d) (ii), (iii) and (iv)
Answer Key:
b) (ii), (iv) and (v)

18. How many electrons in an atom with atomic number 105 can have (n + 1) = 8?
a) 30
b) 17
c) 15
d) unpredictable
Answer Key:
b) 17

19. Electron density in the yz plane of 3d_xy  orbital is
a) zero
b) 0.50
c) 0.75
d) 0.90
Answer Key:
a) zero

20. If uncertainty in position and momentum are equal, then minimum uncertainty in velocity is
a) $\frac{1}{\mathrm{m}}\sqrt{\frac{\mathrm{h}}{\mathrm{\pi }}}$
b)$\frac{\mathrm{}}{}\sqrt{\frac{\mathrm{ h}}{\mathrm{\pi }}}$
c)$\frac{\mathrm{ 2}}{\mathrm{m}}\sqrt{\frac{\mathrm{h}}{\mathrm{\pi }}}$
d)$\frac{\mathrm{ h}}{4\mathrm{h}}$
Answer Key:
c)$\frac{\mathrm{ 2}}{\mathrm{m}}\sqrt{\frac{\mathrm{h}}{\mathrm{\pi }}}$

21. A macroscopic particle of mass 100 gand moving at a velocity of 100cms^{- 1} will have a de Broglie wavelength of

a) 6.6 x10 ^-29cm

b) 6.6 x10 ^-30cm

c) 6.6 x10 ^-31cm

d) 6.6 x10 ^-32cm

Answer Key:
c) 6.6 x10 ^-31cm

22. The ratio of de Broglie wavelengths of a deuterium atom to that of an α- particle, when the velocity of the former is five times greater than that of later, is
a) 4
b) 0.2
c) 2.5
d) 0.4
Answer Key:
d) 0.4

23. The energy of an electron in the 3rd orbit of hydrogen atom is -E. The energy of an electron in the first orbit will be
a) -3E
b) -E/3

c) -E/9
d) -9E
Answer Key:
d) -9E

24. Time independent Schnodinger wave equation is
a) $\widehat{\mathrm{H}}\mathrm{\psi }=\mathrm{E}\mathrm{\psi }$
b) ${▽}^2\mathrm{\psi }+\frac{8{\mathrm{\pi }}^2}{{\mathrm{h}}^2}(\mathrm{E}+\mathrm{V})\mathrm{\psi }=0$
c) $\frac{{\partial }^2\mathrm{\psi }}{\partial {\mathrm{x}}^2}+\frac{{\partial }^2\mathrm{\psi }}{\partial {\mathrm{y}}^2}+\frac{{\partial }^2\mathrm{\psi }}{\partial {\mathrm{z}}^2}+\frac{2\mathrm{m}}{{\mathrm{h}}^2}(\mathrm{E}+\mathrm{V})\mathrm{\psi }=0$
d) all of these
Answer Key:
a) $\widehat{\mathrm{H}}\mathrm{\psi }=\mathrm{E}\mathrm{\psi }$

$\mathrm{ }$
25. Which of the following does not represent the mathematical expression for the Heisenberg uncertainty principle?
а) $△\mathrm{x}.△\mathrm{p}\ge \mathrm{h}/4\mathrm{\pi }$

$\mathrm{b)}$$△\mathrm{x}.△v\ge \mathrm{h}/4\mathrm{\pi m}$

$\mathrm{c) }$$△\mathrm{E}.△\mathrm{t}\ge \mathrm{h}/4\mathrm{\pi }$

$\mathrm{d) }$$△\mathrm{E}.△\mathrm{x}\ge \mathrm{h}/4\mathrm{\pi }$
Answer Key:$\mathrm{ }$

$\mathrm{d) }$$△\mathrm{E}.△\mathrm{x}\ge \mathrm{h}/4\mathrm{\pi }$

II. Short Answer Questions

11th Chemistry

III. Long Answer Questions

11th Chemistry

IV. Exercise

11th Chemistry