Atoms are made up of a positively charged nucleus surrounded by a cloud of negatively charged electrons. Although the nucleus is typically less than one-tenth the size of the atom, it contains more than 99.9% of the atom’s mass. A nuclear force holds together positively charged protons and electrically neutral neutrons to form nuclei. This force is much stronger than the electrostatic force that binds electrons to the nucleus, but its range is only 1 x 10-15 metres.
There are currently 118 known elements, which are typically represented on the periodic table of the elements. Elements with atomic numbers 1 through 98 have all been found in nature, whereas elements with atomic numbers 99 through 118 have only ever been created artificially.
Download PDF of Class 11 Chemistry Chapter 2 Structure of Atom – Set 3
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CBSE Class 11 Chemistry Worksheet Chapter 2 Structure of Atom – Set 3
Q1. What is the maximum number of orbitals that can be identified with the following quantum numbers?
n = 3, l = 1, ml = 0
a.) 1
b.) 2
c.) 3
d.) 4
Q2. The total number of atomic orbitals in the fourth energy level of an atom is ___.
a.) 8
b.) 16
c.) 32
d.) 4
Q3. The magnetic quantum number for the valence electron of potassium is:
a.) 0
b.) 1
c.) 2
d.) 7
Q4. Two electrons occupying the same orbital are distinguished by:
a.) Spin quantum number
b.) Azimuthal quantum number
c.) Magnetic quantum number
d.) Principal quantum number
Q5. Which of the following transitions will have minimum wavelength?
a.) n2 → n1
b.) n3 → n1
c.) n4 → n2
d.) n4 → n1
Q6. Define the shielding effect.
Q7. What are the properties of cathode rays?
Q8. Define isotopes, isobars and isotones.
Q9.
i.) What will be the maximum number of electrons present in an atom having n + l = 4?
ii.) What are the quantum numbers of the valence electrons in a potassium atom (Z = 19) in the ground state?
iii.) How many spherical modes do you expect in a 4s orbital?
Q10. The wavelength of a spectral line of caesium is 460 nm. Calculate the frequency of the line.
Q11. Find out the number of waves made by a Bohr electron in one complete revolution in its 3rd orbit.
Q12. Define:
i.) Black body radiation
ii.) Photoelectric effect
Q13. In Rutherford’s experiment, generally, the thin foil of heavy atoms, like gold, platinum, etc., was used to be bombarded by the É‘-particles. If the thin foil of light atoms like aluminium, etc., is used, what difference would be observed from the above results?
Q14. What is the maximum number of electrons in:
i.) A principal quantum number
ii.) An orbital
iii.) p-subshell
iv.) s, p and d- subshells in an atom
Q15. Why was a change in the Bohr model of atom required? Due to which important developments, the concept of movement of an electron in orbit was replaced by the concept of probability of finding an electron in an orbital? What is the name given to the changed model of the atom?
Q16. The radius of the fourth orbit in a hydrogen atom is 0.85 nm. Calculate the velocity of the electron in this orbit (mass of electron = 9.1 × 10–31 kg)
Q17. Emission transitions in the Paschen series end at orbit n = 3 and start from orbit n and can be represented as v = 3.29 × 1015 (Hz) [1/32 – 1/n2].
Calculate the value of n if the transition is observed at 1285 nm. Find the region of the spectrum.
Q18. Calculate the ratio of the wavelength of the first spectral line of the Lyman and Balmer series of the hydrogen spectrum.
Q19. Calculate:
i.) The energy of a photon of light having a frequency of 3.0 × 1015 s–1.
ii.) The minimum amount of energy that the photons must possess to eject electrons from caesium metal. The threshold frequency of the metal is 4.6 × 1014 s–1.
Q20. Calculate the wavelength for the emission transition if it starts from the orbit having a radius of 1.3225 nm and ends at 211.6 pm. Name the series to which this transition belongs and the region of the spectrum.
Download PDF to access answers of the Chemistry Worksheet for Class 11 Chemistry Chapter 2 Structure of Atom Set – 3.
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Read Also:
- Class 11 Chemistry Chapter 2 Structure of Atom MCQs
- Important Questions for Class 11 Chemistry Chapter 2 Structure of Atom
- Chemistry Concept Questions and Answers
- CBSE Class 11 Chemistry Practical
- Aufbau Principle
- Subatomic Particles
- Rutherford Atomic Model
- Planck’s Quantum Theory: Quantization of Energy
- Bohr’s Model of an Atom
