<u>Answer:</u> The size of the atoms increases as the atomic number of the elements in Group II-A increases.
<u>Explanation:</u>
Atomic radius of an atom is defined as the total distance from the nucleus to the outermost shell of the atom.
On moving from top to bottom, an extra shell around the nucleus is added and the outermost shell gets far away from the nucleus and hence, the distance between the nucleus and outermost shell increases. Thus, increasing the atomic radii of the atom on moving from top to bottom.
We are given:
Atoms that are present in Group II-A are Beryllium (Z = 4), Magnesium (Z = 12), Calcium (Z = 20), Strontium (Z = 38), Barium (Z = 56) and Radium (Z = 88)
As, the atomic number increases on moving down the group, so does the atomic radius of the atoms in the group.
Hence, the size of the atoms increases as the atomic number of the elements in Group II-A increases.
