Chem calculate the wavelength of an electromagnetic wave with a frequency of (in pic)

we have,

wavelenght=c/f

where c= 3×10^8 m/s

f=6.3×10^12 s^-1

so wavelength=(3×10^8)/(6.3×10^12)

=0.476×10^-4 m

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.