Question

Which has largest size ?
(a) Sc3+
(c) La3+
(b) y3+
(d) Ac3+
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Answer 1

b y3+ it is largest size

Answer 2

Among the followin four ions of the elements of group three of the periodic table Ac(3+) has the largest ionic radius.

• Sc belongs to period 4 , Y belongs to period 5, La belongs to period 6 and Ac belongs to period 7 of the periodic table.
• Hence , going doun the period in a group of the periodic table , the size increases due to addition of an extra shell.
• There was a possibility of the size decreasing from yitrium onwards due to participation of poorly screening f-subshells, but in this case the addition of newer shell dominates over presence of f-subshell.