What is the frequency of an electromagnetic wave with energy of 5.0 x 10-20
j?

7.546 × 10^13 Hz

In this case;

Energy, E = 5.0 × 10^-20 Joules

We are required to find the frequency, f

Using the equation;

E = hf

f = E ÷ h

 = 5.0 × 10^-20 J ÷ 6.626 × 10^-34 J-s

= 7.546 × 10^13 Hz

= 7.55 × 10^13 Hz

Thus, the frequency of the electromagnetic wave is 7.55 × 10^13 Hz

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.