Answer:
The C4+ ion has the smallest ionic radius
Explanation:
In the periodic table, the size of an atom increases on going downwards in a group.
On the other hand, in a period, size decreases on going from left to right
The size of cation is smaller than its parent atom.
Lithium-ion (Li+) is the most left so it has the biggest radius.
More to the right ( this means a smaller ionic radius) , we have Berylium-ion (Be2+).
More to the right, so smaller than Be2+, we have B3+
The ion the most to the right, we have C4+
The C4+ ion has the smallest ionic radius
Li+ > Be2+ > Be3+ > C4+
