Liquid bromine easily evaporates. explain what happens to the particles when a liquid evaporates

If the atomic mass of an atom is 34 and the atom contains 13 protons, how many neutrons does the atom contain?

In a laboratory, 1.55mg of an organic compound containing carbon, hydrogen, and oxygen is burned for analysis. this combustion resulted in the formation of 1.45mg of carbon dioxide and .89 mg of water. what is the empirical formula for this compound?

Who discovered a pattern to the elements in 1869?