The atomic size of Ga is smaller than $\mathrm{Al}$ because

The atomic size of Ga is smaller than $\mathrm{Al}$ because
  1. Poor shielding effect of electrons in d-orbitals, effective nuclear charge increases in
    Gallium
  2. More shielding effect of d-electrons
  3. Poor shielding effect of f-orbitals in Gallium
  4. High shielding effect of $3 \mathrm{~s}, 3 \mathrm{p}$ and $3 \mathrm{~d}$ electrons

Solution

Lesser the shielding effect, more will be force of attraction between valence electron and
Incleus, smaller will be atomic size ^

Asked in: JEE-TOPICTESTS-CHEMISTRY

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