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Classification of Elements and Periodicity in Properties — Chemistry STD 11 Science — Question

Gujarat BoardEnglish MediumSTD 11 ScienceChemistryClassification of Elements and Periodicity in Properties3 Marks
Question
Among the elements B, Al, C and Si:
  1. Which has the highest first ionization enthalpy?
  2. Which has the most negative electron gain enthalpy?
  3. Which has the largest atomic radius?
Give reasons.
✓

Answer

  1. Ionization energy increases along a period but decreases going down in the group. Hence, carbon has highest first ionization enthalpy since it has the smallest size among all.
  2. Electron gain enthalpy becomes more negative along a period and less negative down a group, thus, carbon has the most negative electron gain enthalpy due to smallest size.
  3. Atomic radii decrease along a period but increase down the group, thus, Al has the largest atomic radius.

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