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JEE Mains · Chemistry · STD 11 - 3. Classification of elements and periodicity in properties

In a period, the first ionisation enthalpy of the element at extreme left and the negative electron gain enthalpy of the extreme right element, except noble gases, are respectively.

  1. A lowest and lowest
  2. B highest and lowest
  3. C lowest and highest
  4. D highest and highest
Verified Solution

Answer & Solution

Correct Answer

(C) lowest and highest

Step-by-step Solution

Detailed explanation

In a period, as we move from left to right, the atomic size decreases and the effective nuclear charge increases. Due to the large atomic size and low effective nuclear charge, the element at the extreme left (alkali metal) has the lowest first ionisation enthalpy in the period.…