Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
AIIMS2019ChemistryClassification of Elements and Periodicity in Properties

The correct order of decreasing first ionisation energy is

Options

  1. AC > B > Be > Li
  2. BC > Be > B > Li
  3. CB > C > Be > Li
  4. DBe > Li > B > C

Correct answer

B. C > Be > B > Li

Step-by-step solution

In general as we move from left to right in a period, the ionisation enthalpy increases with increasing atomic number. Be (1 s^2 2 s^2 ) has higher ionisation enthalpy than B (1 s^2 2 s^2 2 p^1 ) because Be has fully filled stable electronic configuration.

Practice Classification of Elements and Periodicity in Properties on Quantrex Academy →

More from Classification of Elements and Periodicity in Properties

Match the following List I List II A. Technetium I. Non-metal B. Fluorine II. Transition metal C. Tellurium III. Lanthanoid D. Dysprosium IV. Metalloid 2026Which of the following properties increases from fluorine to iodine in group? 2026Identify the metalloid element from the following. 2026Which among the following elements does NOT exhibit -2 oxidation state? 2026Which has the maximum electropositive character? 2026The hydride with lowest acid strength among the following is 2026Among the following options, the correct trend in the electron gain enthalpy is 2026Given below are two statements : One is labelled as Assertion A and the other is labelled as Reason R . Assertion A : The first ionization enthalpy of O is lower than that of N and 2026 Full Classification of Elements and Periodicity in Properties list All AIIMS PYQs