Chemistry · Textbook solutions

Structure of Atom

Every solved example, exercise, and miscellaneous question — in the order the textbook teaches them. · 45 questions

4. Structure of Atom — worked examples

12 q

Solved Problems 4.1 – 4.12

Worked · 12
  1. Solved Ex.4.1
    Find out the number of protons, electrons and neutrons in the nuclide 1840Ar^{40}_{18}\mathrm{Ar}.
  2. Solved Ex.4.2
    The two natural isotopes of chlorine, viz. 1735Cl^{35}_{17}\mathrm{Cl} and 1737Cl^{37}_{17}\mathrm{Cl} exist in relative abundance of 3:1. Find out the average atomic mass of chlorine.
  3. Solved Ex.4.3
    Three elements Q, R and T have mass number 40. Their atoms contain 22, 21 and 20 neutrons, respectively. Represent their atomic composition with appropriate symbol.
  4. Solved Ex.4.4
    Visible light has wavelengths ranging from 400 nm (violet) to 750 nm (red). Express these wavelengths in terms of frequency (Hz). (1 nm =10−9= 10^{-9} m)
  5. Solved Ex.4.5
    Parameters of blue and red light are 400 nm and 750 nm respectively. Which of the two is of higher energy ?
  6. Solved Ex.4.6
    How many electrons are present in 12H^{2}_{1}\mathrm{H}, 2He_{2}\mathrm{He} and He⊕\mathrm{He^{\oplus}} ? Which of these are hydrogen like specis?
  7. Solved Ex.4.7
    Calculate the radius and energy associated with the first orbit of He⊕\mathrm{He^{\oplus}}.
  8. Solved Ex.4.8
    What is the wavelength of the photon emitted during the transition from the orbit of n=5n = 5 to that of n=2n = 2 in hydrogen atom?
  9. Solved Ex.4.9
    How many orbitals make the N shell? What is the subshell wise distribution of orbitals in the N shell?
  10. Solved Ex.4.10
    An atom has two electrons in its 4s orbital. Write the values of the four quantum numbers for each of them.
  11. Solved Ex.4.11
    Write electronic configuration of 18Ar_{18}\mathrm{Ar} and 19K_{19}\mathrm{K} using orbital notation and orbital diagram method.
  12. Solved Ex.4.12
    Find out one dinegative anion and one unipositive cation which are isoelectronic with Ne atom. Write their electronic configuration using orbital notations and orbital digram method.

Exercises

33 q

1. Choose correct option

Practice · 5
  1. Choose correct option.
    Ex Q.1 (A)
    The energy difference between the shells goes on ........... when moved away from the nucleus.
    1. A.
      Increasing
    2. B.
      decreasing
    3. C.
      equalizing
    4. D.
      static
  2. Ex Q.1 (B)
    The value of Plank's constant is -
    1. A.
      6.626×10−34 Js6.626 \times 10^{-34}\ \mathrm{Js}
    2. B.
      6.023×10−24 Js6.023 \times 10^{-24}\ \mathrm{Js}
    3. C.
      1.667×10−28 Js1.667 \times 10^{-28}\ \mathrm{Js}
    4. D.
      6.626×10−28 Js6.626 \times 10^{-28}\ \mathrm{Js}
  3. Ex Q.1 (C)
    p-orbitals are....... in shape.
    1. A.
      spherical
    2. B.
      dumb bell
    3. C.
      double dumbell
    4. D.
      diagonal
  4. Ex Q.1 (D)
    "No two electrons in the same atoms can have identical set of four quantum numbers". This statement is known as -
    1. A.
      Pauli's exclusion principle
    2. B.
      Hund's rule
    3. C.
      Aufbau rule
    4. D.
      Heisenberg uncertainty principle
  5. Ex Q.1 (E)
    Principal Quantum number describes-
    1. A.
      shape of orbital
    2. B.
      size of the orbital
    3. C.
      spin of electron
    4. D.
      orientation of in the orbital electron cloud

2. Make the pairs

Practice · 1
  1. Ex Q.2
    Make the pairs:
    'A''B'
    a. Neutronsi. six electrons
    b. p-orbitalii. −1.6×10−19 C-1.6 \times 10^{-19}\ \mathrm{C}
    c. charge on electroniii. Ultraviolet region
    d. Lyman seriesiv. Chadwick

3. Complete the following information about the isotopes in the chart given below

Practice · 1
  1. Ex Q.3
    Complete the following information about the isotopes in the chart given below :
    SubstanceMass NumberNumber of ProtonsNumber of NeutronsNumber of Electrons
    Carbon-14
    Lead-208
    Chlorine-35
    Uranium-238
    Oxygen-18
    Radium-223
    (Hint: Refer to Periodic Table if required)

4. Match the following

Practice · 1
  1. Ex Q.4
    Match the following :
    ElementNo. of Neutron
    a. 1840Ar^{40}_{18}\mathrm{Ar}i. 7
    b. 614C^{14}_{6}\mathrm{C}ii. 21
    c. 1940K^{40}_{19}\mathrm{K}iii. 8
    d. 714N^{14}_{7}\mathrm{N}iv. 22

5. Answer in one sentence

Practice · 5
  1. Answer in one sentence :
    Ex Q.5 (A)
    If an element 'X' has mass number 11 and it has 6 neutrons, then write its representation.
  2. Ex Q.5 (B)
    Name the element that shows simplest emission spectrum.
  3. Ex Q.5 (C)
    State Heisenberg uncertainty principle.
  4. Ex Q.5 (D)
    Give the names of quantum numbers.
  5. Ex Q.5 (E)
    Identify from the following the isoelectronic species: Ne\mathrm{Ne}, O2−\mathrm{O^{2-}}, Na+\mathrm{Na^{+}} OR Ar\mathrm{Ar}, Cl2−\mathrm{Cl^{2-}}, K⊕\mathrm{K^{\oplus}}

6. Answer the following questions

Practice · 20
  1. Answer the following questions.
    Ex Q.6 (A)
    Differentiate between Isotopes and Isobars.
  2. Ex Q.6 (B)
    Define the terms: i. Isotones ii. Isoelectronic species iii. Electronic configuration
  3. Ex Q.6 (C)
    State and explain Pauli's exclusion principle.
  4. Ex Q.6 (D)
    State Hund's rule of maximum multiplicity with suitable example.
  5. Ex Q.6 (E)
    Write the drawbacks of Rutherford's model of an atom.
  6. Ex Q.6 (F)
    Write postulates of Bohr's Theory of hydrogen atom.
  7. Ex Q.6 (G)
    Mention demerits of Bohr's Atomic model.
  8. Ex Q.6 (H)
    State the order of filling atomic orbitals following Aufbau principle.
  9. Ex Q.6 (I)
    Explain the anomalous behavior of copper and chromium.
  10. Ex Q.6 (J)
    Write orbital notations for electrons in orbitals with the following quantum numbrs. a. n=2, l=1n = 2,\ l = 1 b. n=4, l=2n = 4,\ l = 2 c. n=3, l=2n = 3,\ l = 2
  11. Ex Q.6 (K)
    Write electronic configurations of Fe, Fe2+\mathrm{Fe^{2+}}, Fe3+\mathrm{Fe^{3+}}
  12. Ex Q.6 (L)
    Write condensed orbital notation of electonic configuration of the following elements: a. Lithium (Z=3) b. Carbon (Z=6) c. Oxygen (Z=8) d. Silicon (Z=14) e. Chlorine (Z=17) f. Calcium (Z=20)
  13. Ex Q.6 (M)
    Draw shapes of 2s and 2p orbitals.
  14. Ex Q.6 (N)
    Explain in brief, the significance of azimuthal quantum number.
  15. Ex Q.6 (O)
    If n=3n = 3, what are the quantum number ll and mm?
  16. Ex Q.6 (P)
    The electronic configuration of oxygen is written as 1s2 2s2 2px 2 2py 1 2pz 11s^2\ 2s^2\ 2p_x^{\,2}\ 2p_y^{\,1}\ 2p_z^{\,1} and not as 1s2 2s2 2px 2, 2py 2 2pz 01s^2\ 2s^2\ 2p_x^{\,2},\ 2p_y^{\,2}\ 2p_z^{\,0}, Explain.
  17. Ex Q.6 (Q)
    Write note on 'Principal Quantum number.
  18. Ex Q.6 (R)
    Using concept of quantum numbers, calculate the maximum numbers of electrons present in the 'M' shell. Give their distribution in shells, subshells and orbitals.
  19. Ex Q.6 (S)
    Indicate the number of unpaired electrons in : a. Si (Z=14) b. Cr (Z=24)
  20. Ex Q.6 (T)
    An atom of an element contains 29 electrons and 35 neutrons. Deduce- a. the number of protons b. the electronic configuration of that element