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

For the elements of the third period, which of the following represents the correct increasing order of first ionization enthalpy?

Options

  1. ANa < Al < Mg < Si < S < P
  2. BNa < Mg < Al < Si < P < S
  3. CNa < Al < Mg < Si < P < S
  4. DNa < Mg < Al < Si < S < P

Correct answer

A. Na < Al < Mg < Si < S < P

Step-by-step solution

Generally, first ionization enthalpy increases across a period from left to right due to an increase in effective nuclear charge. However, there are exceptions due to stable electronic configurations: 1. Magnesium ( 3s^2 ) has a fully filled s -orbital, which is more stable than the 3s^2 3p^1 configuration of Aluminium. The 3s electrons are also more penetrating than the 3p electron. Thus, the first ionization enthalpy of Mg is greater than that of Al. 2. Phosphorus ( 3s^2 3p^3 ) has an exactly half-filled p -subsh

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 NEET PYQs