Suppose you know the number of protons in an atom. What other information would you need in order to determine the mass of the atom? Explain your reasoning

Nebulae are enormous clouds in outer space. they are made mostly of hydrogen gas, helium gas, and dust. some nebulae glow brightly, while others do not. the stars that people see are huge, bright balls of glowing gas. they are made mostly of hydrogen and helium. which statement correctly describes other ways in which nebulae and stars are different? a. stars can form inside a nebula but a nebula can never be produced by any star. b. a star always has a higher density than a nebula. c. stars can never form inside a nebula but a nebula can be produced by any star. d. a nebula always has a higher density than a star.

Calculate the energy required to ionize a hydrogen atom to an excited state where the electron is initially in the n = 5 energy level. report your answer in kilojoules

Use the periodic table to complete this equation that represents nuclear fission processesun - ba c 3 n