1. Tardigrade
  2. Question
  3. Chemistry
  4. Assertion: The atomic size generally increases across a period and decreases down the group. Reason: Atomic size depends upon valence shell electronic configuration.

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Q. Assertion : The atomic size generally increases across a period and decreases down the group.
Reason : Atomic size depends upon valence shell electronic configuration.

Classification of Elements and Periodicity in Properties

Solution:

Along a period, effective nuclear charge increases more than the shielding of inner electrons and thus the size of the atom decreases. Along a group, as the size of the shell increases and so is the shielding of inner electrons, thus down the group the size of the atom increases downwards. Both Assertion and Reason are incorrect.