Question

exam 1
which characteristic is not a periodic trend?
o atomic radius
o electron affinity
o ionization energies
o number of elements in a group

Explanation:

Atomic radius, electron affinity, and ionization energies show trends across periods and groups in the periodic table. However, the number of elements in a group is a fixed - characteristic for each group and not a periodic trend that varies in a regular way across the table.

Answer:

number of elements in a group