What is the wavelength of a photon with a frequency of 4.72 x 1014 Hz? A. 635 nm
B. 142 nm
C. 421 nm
D. 313 nm

Fine out your self ponk

Don’t know. don’t care.look it up on google

B.1 - hydrogren-1 can only mean there is 1 neutron. it's obvious there is 1 proton or else it wouldn't be hydrogen, so they wouldn't put a number after it unless they were indicating the number of neutrons