COMPASSLearning
RegisterLogin

JEE Main · 2019 · 12 Apr 2019 · Shift 2 · Classification of Elements and Periodicity

WhatsApp Email
In comparison to boron, berylium has:
  1. (A)greater nuclear charge and greater first ionisation enthalpy
  2. (B)lesser nuclear charge and lesser first ionisation enthalpy
  3. (C)greater nuclear charge and lesser first ionisation enthalpy
  4. (D)lesser nuclear charge and greater first ionisation enthalpy✓ Correct

Answer: (D)

Solution

Beryllium () carries a smaller nuclear charge than boron (), yet its first ionisation enthalpy is larger. The reason is that beryllium's electron leaves a filled, stable shell, whereas boron loses a single, loosely held electron. So beside boron, beryllium has lesser nuclear charge but greater first ionisation enthalpy.

JEE Main · 2019 · 12 Apr 2019 · Shift 2 · Single correct option

Practise more: all JEE Main PYQs on Classification of Elements and Periodicity →

More JEE Main questions on Classification of Elements and Periodicity

  1. Which of the following represents the correct trend for the mentioned property?
    A. - First Ionization Energy
    B. - Electron Affinity
    C. …
    JEE Main 2026View solution →
  2. Given below are two statements:

    Statement-I: The correct order in terms of atomic/ionic radii is .

    Statement-II: The correct order in terms of the magnitude of electron gain enthalpy is …
    JEE Main 2026View solution →
  3. Given below are two statements :

    Statement-I : The first ionization enthalpy of Cr is lower than that of Mn.
    Statement-II : The second and third ionization enthalpies of Cr are higher than those of Mn .

    In the light of the above statements, choose the correct answer from the op …
    JEE Main 2026View solution →
  4. Given below are two statements :

    Statement-I : is the correct order in terms of first ionization enthalpy values.

    Statement-II : is the correct order in terms of the ma …
    JEE Main 2026View solution →
  5. The correct trend in the first ionization enthalpies of the elements in the period of periodic table is:
    JEE Main 2026View solution →
  6. The correct statements from the following are :
    (A) Ionic radii of trivalent cations of group 13 elements decreases down the group.
    (B) Electronegativity of group 13 elements decreases down the group.
    (C) Among the group 13 elements, Boron has highest first ionisation enthalpy.
    ( …
    JEE Main 2026View solution →