An element is a pure substance that is defined by the number of protons in which is defined as the atomic number

Compare and contrast the bohr model and the electron cloud models of the atom.

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

Which statement is true about a catalyst? a: a catalyst decreases the rate of the reaction. b. a catalyst is consumed during a chemical reaction. c. a catalyst lowers the activation energy of a reaction. d. a catalyst increases the reactant concentration during a reaction.