Blue-green light has a frequency of about 6x10 to the 14Hz.  Use the
relationship c=ft to find the wavelength of this light in air.  How
does this wavelength compare with the size of an atom, which is about
10 to the the -10 m?

daisy001,

firstly, i want to define the sign: ^ which means "to the power"
eg. "10 to the the -10 m" is the same as "10^(-10) m"

secondly, defining c, f and t
c: light speed
f: frequency
t: wavelength

c = 3 x 10^8 m/s

as the "f" you have given in the question,
f = 6 x 10^14 Hz

since c=ft, 
t = c / f
t = 5 x 10^(-7)m

comparing t to the atom size(1 * 10^(-10) m),
5 x 10^(-7)m / 1 x 10^(-10) m = 5000
so, the wavelength of blue-green light is 5000 times bigger than the atom.

although in such a small scale that of light waves and atoms, 
5000 times is still quite a large difference.

abbychau-ga