Which of the following gases are typically used for colorful lighting when an electric current is applied?
a) hydrogen and helium
b) argon and krypton
c) fluorine and chlorine
d) oxygen and nitrogen

periodic trends is an atom that gets larger as the number of electronic shells increase, the radius of atoms increases as you go down a certain group in the periodic table of elements. in general, the size of an atom will decrease as you move from left to right of a certain period.

give me abc and i will get it for u.