Dermatological bases are classified according to?

What elements have 2 electrons inthe 4s sublevel

How many molecules are found in 1.32 mol of nacl?

If you chip a tooth, most likely you will go to the dentist to have the missing material filled in. currently the material used to fill in teeth is a polymer that is flexible when put in, yet is hardened to the strength of a tooth after irradiation with blue light at a wavelength of 461 nm. what is the energy in joules for a photon of light at this wavelength?