As atomic number increases within group 15 on the periodic table, atomic radius
(1) decreases, only
(2) increases, only
(3) decreases, then increases
(4) increases, then decreases

Answer is: (2) increases, only.

The atomic radius of a chemical element is a measure of the size of its atom.

The atomic radius varies with increasing atomic number, but usually increases because of increasing of number of electrons.

Nitrogen (N), phosphorus (P), arsenic (As), antimony (Sb), bismuth (Bi) and moscovium (Mc) are in group 15 of Periodic table. They have same number of valence electrons (five).

Nitrogen has smallest atomic number and smallest atomic radius.

a saline water is fed to a reverse osmosis unit at flow rate o rotameter connected to reject (retentate) line reads 8 installed in reject and permeate line reads 15.2 milli siemens/cm and 300 micro siemens/com respectively.