In a hydrogen atom, when an electron falls from the fifth to the second energy level, it emits a photon of violet light with a frequency of 6.905 x 10^14 S-1. Calculate the energy of this photon. (Plank's constant, h, is 6.626 X 10^-34) E = hf

Which of the following observations indicates that there is a small, dense, positively charged part in the center of an atom? some uncharged particles are scattered by a gold foil. all uncharged particles are attracted towards a gold foil. all positively charged particles pass straight through a gold foil. some positively charged particles bounce back from a gold foil.

What is the empirical formula of c6h18o3? ch3o c2h5o c2h6o c2h5o5

Suppose you mix one mole of sulfuric acid (h2so4) with 1 mole of sodium hydroxide(naoh). why does the ph of the solution remain below 7? ( explain so i can get better understanding! )