Question

Assertion: The electron gain enthalpies have large negative values toward the upper right of the periodic table preceding the noble gases.
Reason: The effective nuclear charge increases from left to right across a period and consequently it will be easier to add an electron to a smaller atom since the added electron on an average would be closer to the positively charged nucleus.

• A. If both A and R are correct and R is the correct explanation of A.
• B. If both A and R are correct but R is not the correct expalnation of A.
• C. A is true but R is false.
• D. A is false but R is true.
• E. A and R both are false.

Answer 1

Answer: (A)

The electron gain enthalpies have large negative values towards the upper right of the periodic table preceding noble gases because as we move from left to right in a period atomic radii decreases due to increase in effective nuclear charge due to which electron attracting tendency increases and consequently the electron gain enthalpy have larger negative values.