Set 1: Atomic Structure and Related Concepts

1 Mark Questions

1. Fill in the blanks with the correct choice given in brackets:

   • If an element has two electrons in its outermost shell, then it is likely to be a _____ [Metallic / Non-metallic].
   • The first scientific theory about the structure of matter was proposed by _____ [Goldstein / John Dalton].
   • The magnitude of negative charge carried by an electron is _____ [1.6 × 10⁻¹⁹ C / 1.6 × 10¹⁹ C].
   • Bombarding beryllium atoms with alpha particles results in the formation of a carbon isotope and a _____ [Proton / Neutron].
   • The maximum number of electrons in the L shell is _____ [8 / 18].
   • The three isotopes of hydrogen are _____ [Protium / Tritium / Deuterium].

2. Choose the correct options:

   1. Rutherford’s alpha-particle scattering experiment demonstrated that:
      • Electrons revolve around the nucleus.
      • The atom has a dense nucleus.
      • Protons are present in the nucleus.
      • Atoms have valence electrons.
   2. The number of valence electrons in O²⁻ is:
      • 6
      • 8
      • 2
      • 4
   3. The correct electronic configuration of potassium is:
      • 2, 8, 8, 1
      • 2, 8, 1
      • 2, 1
      • 2, 8, 7
   4. The discovery of the electron is credited to:
      • William Crookes
      • J.J. Thomson
      • Goldstein
      • Rutherford
   5. Identify the pair of isotopes:
      • ⁴⁰Ar and ³⁹K
      • ⁴⁰Ar and ⁴⁰K
      • ¹²C and ¹⁴C
      • ³⁰P and ³⁰Si
   6. The electronic configuration of magnesium is:
      • 2, 8, 2
      • 2, 8, 3
      • 2, 8, 4
      • 2, 8

Set 2: Atomic Structure and Related Concepts

3. What is an alpha (α) particle?
4. What is the nature of charge on cathode rays and anode rays?
5. How are X-rays produced?
6. State one observation that shows that an atom is not indivisible.
7. Based on Rutherford’s model of the atom, which subatomic particle is present in the nucleus?
8. Name the fundamental particle discovered by Chadwick.
9. State the major drawback of Rutherford’s model of the atom.
10. What is the significance of the number of protons in the atoms of different elements?
11. Define the term “isobars.”
12. From the symbol ¹²₆C, write down the mass number and atomic number.
13. What is meant by the term “electronic configuration”?
14. Explain why ionic compounds have high melting and boiling points.
15. Name the following:
    • Anions
    • Cations
    • Neutrons
16. Draw the orbit diagram for a helium atom.
17. Identify the missing element and complete the following equation:

    Be + ? → ¹²₆C + ⁴₂He

18. What is the missing element in the reaction:

    ¹⁴₆C → ¹⁴₇N + ?