Answer:
C. The number of shells increases from top to bottom
Explanation:
There are some trends about the periodic table, one of them is that in the vertical columns of periodic table, the number of shells increases from top to bottom.
From top to bottom in a periodic table, the number of electrons increases, thus more number of shells are needed to fill these electrons and the number of shells increases or we can say the atomic radius increases from top to bottom.
Hence, the correct option is "C".
